Four men, Victor Peirce, Trevor Pettingill, Anthony Leigh Farrell and Peter David McEvoy were charged with murder and later acquitted by a jury in the Supreme Court of Victoria. Two other suspects, Jedd Houghton and Gary Abdallah, were shot and killed by Victoria Police before being brought to trial.
In 2005, Wendy Peirce, widow of accused Victor Peirce, gave an interview to media detailing how her late husband had planned and carried out the murders and was actually guilty as charged
On 11 October 1988, Peirce's best friend, Graeme Jensen, was shot and killed by police in Narre Warren.
Jensen had been under observation by the Victoria Police Armed Robbery Squad, who had planned to arrest him in connection with a murder. When detectives attempted to effect the arrest, one of the police cars was delayed in traffic, allowing Jensen to attempt to escape. Police shot and killed Jensen at the scene
On 12 October, thirteen hours later at approximately 4:50am, Constables Tynan and Eyre were operating a divisional van from Prahran police station when called to an abandoned Holden Commodore left in Walsh Street, South Yarra. While the officers were examining the vehicle, they were ambushed by armed offenders. Constable Tynan was cut down with a shotgun while sitting in the car, and Constable Eyre was seriously wounded. Constable Eyre, despite suffering serious injuries, struggled with the attacker until another person approached him from behind and managed to remove Eyre's service revolver from its holster and shot him in the head with it
Police believe members of a Melbourne underworld gang had organised the murders. In the two-year period up to April 1989 there were eleven fatal shootings by police. The execution-style killings of the two police officers was thought by many to have been a payback by prominent members of the Melbourne underworld
The police investigation was known as the Ty-Eyre Task Force, a combination of the two surnames of the officers killed. It was headed by Detective John Noonan and was the biggest investigation Victoria Police had ever undertaken at the time and also the longest running, spanning 895 days. At the height of the investigation, police had hundreds of officers assigned to the task force to investigate the murders, and diverted resources from other major investigations at the time
A gang police dubbed The Flemington Crew had robbed at least four Melbourne banks. The robbers bungled the Oak Park robbery and left shotgun shells at the scene. The shells became the single forensic link police had, linking the shells to the same shotgun used in the Walsh Street murders
Members of the gang responsible for the robberies were believed to be Victor Peirce, Graeme Jensen, Jedd Houghton and Peter David McEvoy. The home of Victor Peirce was raided the day following the Walsh Street shootings. Peirce's house was demolished and the backyard dug up in the search for evidence.
The trial of the 4 men accused, Victor Peirce, Trevor Pettingill, Anthony Leigh Farrell and Peter David McEvoy, began in March, 1991. The prosecution alleged 6 people were involved in the planning of the shootings, Victor Pierce, Trevor Pettingill, Anthony Leigh Farrell and Peter David McEvoy, Jason Ryan and Jedd Houghton
Jason Ryan became a prosecution witness in the trial and was offered immunity in exchange for his testimony. Police placed Ryan under the witness protection program and removed him to Mansfield on 24 October 1988 for questioning, with his evidence changing many times over the course of time between the shootings and the trial Ryan's evidence had implicated Gary Abdallah, Jedd Houghton, Anthony Leigh Farrell, Emmanuel Alexandris. Police were told the party of killers were Jedd Houghton, Peter David McEvoy, Anthony Leigh Farrell and his uncles Victor Peirce and Trevor Pettingill. Abdallah and Houghton were later shot and killed in police raids
A memorial in Kings Domain, Melbourne to Victoria Police officers killed in the line of duty.All four men charged with the murders were acquitted in the Supreme Court of Victoria.
Victor Peirce and Peter David McEvoy were taken into custody on other charges, yelling "We'll be killed, we'll be killed". Victor claimed after his acquittal that he was afraid of police retribution and issued a statement in which he professed his innocence and requested "to be left alone to work and prove to the community I am not as bad as police and the press has made me out to be".
