The opinion of the court was delivered by: Borden, J.
 The defendant appeals *fn1 from the judgment of conviction, following a jury trial, of felony murder in violation of General Statutes § 53a-54c, and of burglary in the first degree in violation of General [235 Conn Page 804]
Statutes § 53a-101(a)(1). *fn2 The defendant claims that the trial court improperly: (1) admitted into evidence the defendant's testimony from a prior trial on the same charges; (2) refused to admit into evidence certain testimony and documents concerning threats made against the defendant by the alleged coparticipant in the crime; (3) refused to admit into evidence certain information concerning the defendant's willingness to take a polygraph test, and the results of that test; and (4) admitted tracking evidence obtained by a police canine. We affirm the judgment of the trial court.
At his first trial in March, 1990, the defendant, James Esposito, was tried before a jury on charges of felony murder, robbery in the first degree and burglary in the first degree. The defendant testified in his defense in that trial. The jury rendered a verdict of guilty on all three counts. The defendant appealed to this court from [235 Conn Page 805]
the judgment of conviction of the trial court, Hadden, J., and we reversed the judgment and ordered a new trial. State v. Esposito, 223 Conn. 299, 613 A.2d 242 (1992). In September and October, 1993, the defendant again was tried before a jury on the same charges. Although the defendant did not testify at the second trial, the state introduced the testimony he had given at the first trial. After the trial court, Fracasse, J., rendered a judgment of conviction in accordance with the jury's verdict, this appeal followed.
The jury reasonably could have found the following facts. On the evening of September 5, 1988, the defendant and his friend, Brian Greco, went to the Orange Blossom Cafe, a bar in Orange. The two men left the bar together between 11 p.m. and 11:30 p.m. when the manager, Nicholas Amendola, Jr., (Amendola, Jr.), closed early.
At approximately 11:30 p.m., Robert Bessinger, Joyce Bessinger and Robert Velardi were in the first-level family room of the Bessingers' four-level home in Hamden. The Bessingers' young daughter was asleep in a third-level bedroom. Robert Bessinger and Velardi stepped into the backyard to shake out a rug while Joyce Bessinger cleaned the family room. Joyce Bessinger heard someone enter the house by the second-level front door and announce, "This is the cops. This is a stickup!" A man whom she did not recognize, wearing jeans and sneakers, then came down into the family room holding a gun.
The man, whom Joyce Bessinger later identified as Greco, demanded to know where the Bessingers kept their money and jewelry. When she did not respond, he asked where the others were. She told him that they were outside and he went out the first-level rear door. Shortly thereafter, Greco, holding Robert Bessinger and Velardi at gunpoint, returned to the [235 Conn Page 806]
family room. At Greco's command, the Bessingers and Velardi lay facedown on the floor. After Greco ordered Robert Bessinger to show him where he kept his valuables, Bessinger led Greco to the third-level bedroom in which he kept two safes.
Before leaving the family room, Greco warned Velardi and Joyce Bessinger to keep their heads down or they would be shot by the "guns" who were watching at the windows. Velardi and Joyce Bessinger heard the footsteps of Greco and Robert Bessinger on the stairs, and then heard their footsteps and voices in the bedroom where the Bessingers' daughter was sleeping. Out of concern for her husband and daughter, Joyce Bessinger listened intently to the noises upstairs.
Velardi then heard another person, the defendant, come downstairs into the family room. Although Velardi could not see the defendant because Velardi's eyes were facing the floor, he believed that a second intruder was in the house because this individual's voice sounded deeper and more arrogant than Greco's, which Velardi described as cold and businesslike. The defendant threatened to shoot Velardi and Joyce Bessinger if they raised their heads. As the defendant walked away, Velardi raised his head slightly and saw that the defendant was wearing blue pants and work boots.
Velardi and Joyce Bessinger then heard the sounds of a struggle upstairs, followed by a single gunshot. At the sound of the shot, Velardi saw the defendant run up the stairs. At the same time, Velardi ran out of the first-level rear door into woods behind the house. Joyce Bessinger fled downstairs into a basement area, where she unscrewed the only light bulb and hid under a desk.
From the basement, Joyce Bessinger heard additional gunshots and the sounds of a struggle coming closer to her. After the third gunshot, she heard something fall down the stairs leading from the second level [235 Conn Page 807]
to the first-level family room. She then heard someone come down those stairs and she heard Greco ask, "Where is the bitch on the floor?" Greco sounded as if he were speaking to another person. She heard no reply.
After several minutes, Joyce Bessinger left the basement to go to her daughter, who was screaming. She climbed the stairs from the basement to the family room, and there she saw her husband, who had been shot and was bleeding profusely, lying at the bottom of the stairs leading from the second level. After retrieving her daughter, she called the police.
Velardi, in the meantime, had run to the neighboring house of Louis Calhoun. Velardi heard sounds of a departing car coming from the direction of the Bessinger house. Calhoun also heard a car leaving at a high rate of speed from the intersection of Paradise Avenue and Howard Drive, which is near the Bessinger house.
The Hamden police arrived at the Bessinger residence at 12:06 a.m. Robert Bessinger died from three gunshot wounds to the head, abdomen and left shoulder.
Joyce Bessinger identified Greco as the gunman from three separate photographic arrays. She and the Hamden police also produced a composite picture of the gunman that she showed to a group of family and friends. Two members of the group, Lori Bessinger, the sister of Robert Bessinger, and her boyfriend, Marco Esposito, the defendant's brother, immediately recognized Greco.
On September 20, 1988, the Hamden police arrested the defendant and charged him with felony murder. Accompanied by his attorney, the defendant later led police to a river in which police divers found the .25 caliber handgun that had been used to kill Robert Bessinger. [235 Conn Page 808]
The defendant first claims that the trial court improperly admitted his testimony from the first trial because that testimony had been compelled by the state's unlawful suppression of evidence in violation of Brady v. Maryland, 373 U.S. 83, 83 S.Ct. 1194, 10 L.Ed.2d 215 (1963). More specifically, the defendant contends that his testimony at the first trial was "compelled" because he was required to testify to counter certain testimony of Nicholas Amendola, Sr., (Amendola, Sr.), which the defendant had been unable to impeach because the state had unlawfully suppressed material impeachment evidence in violation of Brady. The defendant claims that, because his testimony was compelled in this way, its subsequent use at his second trial violated the rule set forth in Harrison v. United States, 392 U.S. 219, 88 S.Ct. 2008, 20 L.Ed.2d 1047 (1968), which prohibits the use of a defendant's unlawfully compelled testimony against him. We disagree.
In order to understand the defendant's claim, it is necessary first to recapitulate the testimony given at the first trial by Amendola, Sr., and by the defendant. At the first trial, Amendola, Sr., gave the following testimony. On September 13, 1988, the defendant and Thomas Corolla went to the Orange Blossom Cafe to see Amendola, Sr., and his son, Amendola, Jr. The Amendolas and the defendant had been arrested together earlier that month for cocaine possession, and they planned to discuss the charges pending against them. The four men left the bar and drove to a parking lot to talk. Amendola, Sr., testified that, during their conversation in the car, the defendant admitted that he and his "cousin" had entered the Bessinger house intending to commit a robbery. Amendola, Sr., also testified that the defendant said that he had stayed downstairs while his cousin took one [235 Conn Page 809]
of the three adults upstairs to the safe, shot him, dragged him downstairs, beat him, and shot him in the back of the neck.
At the first trial, after Amendola, Sr., testified, the defendant gave the following testimony. After leaving the Orange Blossom Cafe with Greco on the night of September 5, 1988, the defendant expected that Greco would take him directly home. During the ride, the defendant fell asleep on a mattress in the back of Greco's truck. He awoke when the truck stopped and Greco left the vehicle, saying, "I'll be right back." After waiting about five minutes, the defendant got out of the truck and began to look for Greco. Although the defendant did not find Greco, he realized that he was very near the home of the Bessingers, whom he knew through his brother Marco. He walked to the Bessinger home because he hoped to use their phone or get a ride home. Through the front screen door, he saw that Greco held a gun and was leading Robert Bessinger up the stairs to the third level of the house.
The defendant testified further that he followed Greco and Robert Bessinger upstairs and attempted unsuccessfully to enter the bedroom. While he was outside banging on the closed door and screaming, he heard sounds of a struggle in the bedroom. After he returned downstairs to the second level, the bedroom door opened and the two men emerged. Greco held the gun with one hand and the collar of Robert Bessinger with the other. When Greco and Robert Bessinger reached the bottom of the stairs, the defendant jumped between them. Greco threw the defendant across the room onto the floor and pointed the gun at him. The defendant covered his face and ran from the house, exiting by the front door.
At the same time, according to the defendant's testimony, Robert Bessinger ran toward the second-level kitchen, in the opposite direction [235 Conn Page 810]
from the stairs leading to the family room where his body was found. Immediately after the defendant ran from the house, while still on the front lawn, he heard three gunshots. Within seconds, Greco emerged from the house by the front door, grabbed the defendant by the arm and dragged him back to the truck.
The defendant claims that his testimony given at the first trial was compelled by the state's failure to disclose a tape recording of a telephone conversation between Amendola, Sr., and Thomas Rhone, a Hamden police officer. On September 14, 1988, the day after his conversation with the defendant, Amendola, Sr., contacted Rhone by telephone and offered to give information about the murder in exchange for a favorable resolution of the drug charges against him and his son. This telephone conversation with Rhone was recorded. During the conversation, which lasted approximately ten minutes, Amendola, Sr., offered to give Rhone information concerning the murder, including "names and everything" if Rhone arranged for the drug charges pending against him and his son to be dropped, and for the return of his car. In attempting to convince Rhone that his information was reliable, Amendola, Sr., told Rhone that the crime occurred at 12:05 a.m., that it involved a "blond-headed kid" with no tattoos, that a .25 caliber pistol was used, and that the victim was shot in the stomach, beaten, kicked and shot in the back of the head. Amendola, Sr., told Rhone that two people were involved, one of whom entered the house through a back window, and the other of whom went up the front stairs. During the recorded conversation, Rhone promised Amendola, Sr., "if the information warrants it," to get his car returned and to go to the prosecutor to get the charges dropped.
After meeting with the police later that evening, Amendola, Sr., made a formal statement. In this statement, Amendola, Sr., described in greater [235 Conn Page 811]
detail the events of the night of September 5, 1988. In summary, he stated that the defendant had told him that he and his cousin had entered the house and had held several people at gunpoint. The cousin shot a man in the stomach, kicked him, and shot him in the back of the head. In another formal statement given September 15, 1988, Amendola, Sr., affirmed parts of his prior statement and added other facts, including that the murder victim led the gunman to the safe and that, contrary to the description of the victim's wife, the gunman did have tattoos but that they were covered the night of the murder.
Amendola, Jr., also made a formal statement on September 14, 1988. He said that he had heard the defendant say that he witnessed a murder in Hamden after he left the Orange Blossom Cafe on September 5, 1988. He also told police that the defendant was at that bar with a friend until approximately 11:30 p.m. that night. When asked to make a photographic identification of the man who left with the defendant, Amendola, Jr., identified Greco.
Both Amendolas testified at the probable cause hearing and the first trial. Prior to the second trial, however, Amendola, Sr., died. The tape recording of his initial telephone conversation with Rhone on September 14, 1988, was not disclosed to the defendant until jury selection began for the second trial in 1993.
When, at the second trial, the state offered into evidence the testimony given by the defendant at the first trial, the defendant objected because of the nondisclosure of the recorded September 14, 1988 conversation between Amendola, Sr., and Rhone. The defendant claimed that, because of the nondisclosure of the tape recording prior to the first trial, he had been denied crucial material for his cross-examination of Amendola, Sr. He further claimed that, because he was unable sufficiently to impeach the testimony of Amendola, Sr., [235 Conn Page 812]
he was "compelled" at the first trial to testify in order to counter that testimony. The trial court rejected the defendant's claim that he had been unconstitutionally compelled to testify by the nondisclosure, ruling that the tape recording provided "little more than cumulative material" with which to impeach the credibility of Amendola, Sr., which had been extensively attacked at the first trial. We agree with the trial court.
As a general rule, the defendant's testimony at a former trial is admissible against the defendant in later proceedings. Harrison v. United States, supra, 392 U.S. 222; State v. Castonguay, 218 Conn. 486, 491, 590 A.2d 901 (1991). To avoid the application of this rule, the defendant relies upon United States Supreme Court precedent enunciated in Harrison v. United States, supra, 219, and Brady v. Maryland, supra, 373 U.S. 83. In Harrison, the defendant testified after the admission into evidence of several confessions. Harrison's conviction was reversed on appeal because the confessions had been obtained illegally. On retrial, his prior testimony was admitted over his objection that the testimony should be excluded because it had been induced by the use of the illegal confessions. Reversing Harrison's second conviction, the United States Supreme Court held that the principle of the fruit of the poisonous tree, which prohibits the use of illegally obtained confessions, also "prohibits the use of any testimony impelled thereby." Harrison v. United States, supra, 222.
The defendant attempts to link the doctrines set forth in Harrison and Brady. He argues that because Brady prohibits the suppression of material exculpatory evidence, and because, in his view, the failure of the state to disclose to him at his first trial the recorded September 14, 1988 conversation between Amendola, Sr., and Rhone constituted a Brady violation, application of the Harrison principle requires the conclusion [235 Conn Page 813]
that the defendant's testimony at the first trial was "compelled." More specifically, the defendant contends that this record demonstrates that, as a matter of law, his testimony at the first trial was given only to counter the tainted inculpatory testimony of Amendola, Sr., and thus was "compelled" and inadmissible in the second trial. We disagree.
To dispose of the defendant's claim, we need not reach several issues raised by his arguments. Specifically, we need not decide whether, as a matter of fact, the defendant would have testified in the first trial if the state had disclosed the tape recording. Nor need we decide whether Harrison, which involved an antecedent illegally obtained confession by the defendant, governs the admissibility of prior testimony if the antecedent impropriety is a Brady violation related to the testimony of a witness. We need not reach these issues because we agree with the trial court that the undisclosed evidence was cumulative of other evidence at the first trial and, therefore, no Brady violation occurred.
In Brady v. Maryland, supra, 373 U.S. 87, the United States Supreme Court held "that the suppression by the prosecution of evidence favorable to an accused . . . violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution." To establish a Brady violation, the defendant must show that (1) the government suppressed evidence, (2) the suppressed evidence was favorable to the defendant, and (3) it was material. State v. White, 229 Conn. 125, 134-35, 640 A.2d 572 (1994); Demers v. State, 209 Conn. 143, 150, 547 A.2d 28 (1988). *fn3 It is well established that "`[i]mpeachment [235 Conn Page 814]
evidence as well as exculpatory evidence falls within Brady's definition of evidence favorable to an accused.'" State v. Gant, 231 Conn. 43, 52, 646 A.2d 835 (1994), cert. denied, ___ U.S. ___, 115 S.Ct. 1404, 131 L.Ed.2d 291 (1995); State v. White, supra, 135; State v. McPhail, 213 Conn. 161, 167, 567 A.2d 812 (1989); State v. Pollitt, 205 Conn. 132, 142, 531 A.2d 125 (1987).
The United States Supreme Court further defined the Brady rule in United States v. Bagley, 473 U.S. 667, 682, 105 S.Ct. 3375, 87 L.Ed.2d 481 (1985), holding that undisclosed exculpatory evidence is material, and that constitutional error results from its suppression by the government, "if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding would have been different. A `reasonable probability' is a probability sufficient to undermine confidence in the outcome." The United States Supreme Court recently discussed several aspects of materiality under Bagley that "bear emphasis." Kyles v. Whitley, ___ U.S. ___, 115 S.Ct. 1555, 1565-66, 131 L.Ed.2d 490 (1995). The court explained that a showing of materiality "does not require demonstration by a preponderance that disclosure of the suppressed evidence would have resulted ultimately in the defendant's acquittal." Id., 1566. "The question is not whether the defendant would more likely than not have received a different verdict with the evidence, but whether in its absence he received a fair trial, understood as a trial resulting in a verdict worthy of confidence." Id. The United States Supreme Court also emphasized that the Bagley test is not a sufficiency of evidence test. Id. "A defendant need not demonstrate that after discounting the inculpatory evidence in light [235 Conn Page 815]
of the undisclosed evidence, there would not have been enough left to convict. . . . One does not show a Brady violation by demonstrating that some of the inculpatory evidence should have been excluded, but by showing that the favorable evidence could reasonably be taken to put the whole case in such a different light as to undermine confidence in the verdict." Id.
In the present case, the state does not contest that the tape of the recorded conversation was "suppressed," within Brady parlance, prior to the first trial. Although the prosecution did not obtain the tape recording until after the commencement of the second trial, the record is clear that the police possessed the recording within days of the homicide; for Brady purposes "[p]olice are treated as an arm of the prosecution." (Internal quotation marks omitted.) State v. Gant, supra, 231 Conn. 53; State v. White, supra, 229 Conn. 135; Demers v. State, supra, 209 Conn. 153.
The state contends, however, that the undisclosed tape recording was neither favorable to the defendant nor material in the constitutional sense. The state argues that, although impeachment evidence generally constitutes favorable evidence for the purposes of Brady, this evidence was not favorable because the recording's impeachment value was extremely limited or nonexistent. Moreover, the state contends that the recording was not material under the Brady doctrine because it contains no information that contradicts directly or indirectly the other statements or trial testimony of Amendola, Sr. We need not determine whether the evidence constitutes favorable Brady evidence because we agree with the state and the trial court that the tape recording is not material.
"It is well established that impeachment evidence may be crucial to a defense, especially when the state's case hinges entirely upon the credibility of certain key [235 Conn Page 816]
witnesses. . . . The rule laid out in Brady requiring disclosure of exculpatory evidence applies to materials that might well alter . . . the credibility of a crucial prosecution witness. . . . Still, the seminal test remains whether there exists a reasonable possibility that the outcome of the proceeding would have been different had the evidence been disclosed to the defense." (Citations omitted; internal quotation marks omitted.) State v. Gant, supra, 231 Conn. 53. *fn4
At the first trial, Amendola, Sr., testified that the defendant had told him that he had been at the Bessinger residence on the night of the murder and had participated in the burglary. Amendola, Sr., testified in detail about the burglary and the murder of Robert Bessinger. Although the details of his testimony and statements sometimes varied, his account did not ...