The nearly 25-year-old murder of a former Toronto school board trustee – one flagged by police for possible connections to serial killer Bruce McArthur – has been solved after a DNA match identified his suspected, and deceased, killer.

Dennis Joseph Colby, 47, was found dead in his apartment on Cosburn Avenue in East York on Sept. 12, 1995, three days after he was last seen alive.

Detectives determined that Mr. Colby, who had served as a school board trustee from 1974 to 1978, had been beaten to death. Numerous people were interviewed by police, including friends, family and neighbours who had heard a noise at the time, but no one was ever arrested.

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The case was brought back into the news media spotlight last year after it was one of more than 20 flagged for review by Toronto police in light of the January, 2018, arrest of Mr. McArthur, a now-convicted serial killer.

Mr. McArthur’s involvement was ruled out when DNA evidence produced a match in the Colby case late last year. But the suspect’s name is not being released and no charges will be laid because he died in 2015. Detective Sergeant Stacy Gallant described the man, who would have been 26 in 1995, as a drifter who had been staying with Mr. Colby when he was killed.

Mr. McArthur, a 67-year-old landscaper, pleaded guilty in January to eight counts of first-degree murder of men with ties to Toronto’s Gay Village, dating back to 2010.

Because Mr. Colby was gay and there was a personal or “close-contact” element to his killing, Det. Sgt. Gallant said it was one investigators felt warranted further review. However, he said that ultimately there were no links in this case to Mr. McArthur.

The city’s LGBTQ community had long raised concerns about a potential serial killer, and both external and internal reviews have been commissioned into the police service’s handling of vulnerable missing people. A special missing persons unit has also been established.

As part of an unrelated review of cases in 2016, Det. Sgt. Gallant sent off evidence from 45 cold cases for DNA comparison testing through Canada’s national data bank. Although DNA comparison was used by police in the late 1990s, Canada only launched its National DNA Data Bank in 2000 – five years after Mr. Colby was killed.

As of the end of 2018, according to statistics from the RCMP, the data bank included DNA profiles from 379,732 convicted offenders and 155,346 crime scenes.

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According to the “match inventory report,” the data bank has enabled investigators to match 54,513 DNA samples from crime scenes to offenders, and have been able to link close to 6,000 crime scenes to other scenes.

In Mr. Colby’s case, they hit a match. The suspect was not on the police’s radar at the time and was never interviewed in this case but he “strongly resembled” a composite drawing that had been produced at the time, police said.

Although he was in the DNA data bank as a convicted offender from previous crimes, Det. Sgt. Gallant would say only that the suspect’s record was for crimes of violence. The man was not in custody when he died.

“Had he still been alive today, he would have been arrested and charged with the second degree murder of Dennis Joseph Colby,” the service’s press release noted on Thursday.

Det. Sgt. Gallant said that Mr. Colby’s family was notified of the closing of the case.