A timeline of how police tracked down a Calgary serial killer

In 1976 and 1977, the bodies of four girls and a woman were found in Calgary. For almost 50 years, their deaths were not solved.

On Friday, RCMP identified Gary Allen Sreri, as an American sex offender, murderer. He died in an Idaho prison in 2011.

Here's a look at the police investigation:

February 12, 1976: Eva Dvorak and Patsy McQueen, both 14, leave Jan Bazalgette High School. They spend the next two days together, visiting various friends' homes. McQueen's family reported her missing.

February 15, 1976: The bodies of two girls were found under an overpass west of Calgary. They were fully clothed, but police believe they were sexually assaulted.

September 15, 1976: Melissa Rehorek, 20, is seen by her roommates at the YWCA in downtown Calgary. She tells people that she plans to hitchhike out of Calgary on the weekends when she works as a hotel maid. The next day, her body was found in a ditch along a gravel road outside the city. His body is also fully clothed, with evidence of struggle. An autopsy revealed that she had been strangled.

February 25, 1977: Barbara McLean, 19, attends a cabaret with friends. The bank employee was last seen walking alone from the Highlander Bar at around 2am the next day. His body was found that morning just outside the then-city limits of Calgary. He was also strangled and there were signs of a fight. His jacket is inside out.

READ MORE: Victims' families react after RCMP link serial killer to historic Calgary murders

1990s: Over the years, the RCMP formed four teams to re-examine evidence, tips from the public and any leads previously missed in the four murders.

March 2003: Lab confirms DNA found in Rehorak and McLean's murders is identical.

2023: The DNA profile for Eva and Patsy's killer has been determined, and it is the same profile as Rehorak and McLean's killer. Later that year, a report determined that the DNA could match Gary Allen Sreri, a serial sex offender who fled the United States to Canada in the mid-1970s.

September 13, 2023: Idaho police confirmed that Sreri's DNA matched the genetic profile of DNA from the Calgary murder.