Gary Allen Srery was born on July 26, 1942, in Oak Park, near Chicago, Illinois. He was the eldest of three siblings. In the mid-1950s, his family moved to California, where he spent most of his early years.

Growing up, Srery's family life was relatively normal, but as he got older, he began to show signs of troubling behavior. By the time he was a young adult, he had several run-ins with the law. His criminal activities started with minor offenses but gradually escalated.

Gary Allen Srery's series of murders began in February 1976 and ended in February 1977 in Calgary, Alberta. His victims were all young women between the ages of 14 and 20. Eva Dvorak and Patricia McQueen, both 14 years old, were murdered in February 1976. Their bodies were discovered on February 15. The investigation revealed that they had been asphyxiated. Melissa Ann Rehorek, a 20-year-old woman, was murdered in September 1976. Her body was found in a ditch along a gravel road. She had been strangled, and there were signs of a struggle on her body. Barbara Jean MacLean, a 19-year-old woman, was murdered in February 1977. After leaving the Highlander Hotel following an argument with her boyfriend, her body was found the next day. She was fully clothed, but there were signs of sexual assault.

At the time of these murders, Gary Allen Srery was living illegally in Canada to avoid a rape charge in California. Despite the brutality of his crimes, he managed to evade capture for these murders for many years. In the early 2000s, Srery was convicted of rape in Idaho and was serving a life sentence. He died in prison on April 27, 2011. It wasn't until May 2024, more than a decade after his death, that Srery was publicly identified as the murderer of the four women in Calgary. This identification was made possible through Investigative Genetic Genealogy conducted by genealogists from Convergence Investigative Genetic Genealogy. DNA evidence from the crime scenes was matched to Srery, finally linking him to the murders. Although Srery could not be charged posthumously for these murders, the revelation provided closure to the families of the victims and the community. It also highlighted the advancements in forensic technology and the importance of continued investigation into cold cases.