Hamilton man charged in 2006 Toronto cold case homicide after DNA breakthrough

More than 19 years after 21-year-old Patrick Santos was found strangled to death outside his Toronto home, Toronto Police have charged a Hamilton man with first-degree murder following advances in DNA technology and years of investigative work.

At a news conference at police headquarters on July 30, Detective Sergeant Stephen Smith of the Homicide and Missing Persons Unit's Cold Case Section announced that 43-year-old Pierre O'Connor was arrested on July 29 and charged in connection with the 2006 homicide.

Santos was found dead outside his residence near Ellesmere and Bellamy Rds. on September 17, 2006. His killing was Toronto's 49th homicide of that year.

Smith said investigators never gave up on the case.

“Although more than 19 years have passed since Patrick was killed, investigators never stopped pursuing leads,” he said.

Detectives collected DNA evidence from the scene in 2006, but it did not match anyone in the national DNA database.

In 2020, Toronto Police partnered with Othram Inc. to use Investigative Genetic Genealogy (IGG) in an effort to identify the person responsible.

“While that process did not directly identify a suspect, it generated valuable investigative leads that helped move the case forward,” Smith said.

He said members of the Cold Case Section and the Forensic Identification Services team spent several years developing those leads before identifying a person of interest in 2025. Subsequent DNA testing allegedly linked O'Connor to DNA recovered from the homicide scene.

Investigators are still working to determine the motive for the killing and the nature of the relationship, if any, between O'Connor and Santos.

“We also believe more than one person may have been involved in this murder,” Smith said. “If anyone has information, we are asking them to reach out to police.”

Smith credited the persistence of investigators who worked on the case over nearly two decades.

“This arrest would not have been possible without the work of our tremendous investigators, both past and present, in our Cold Case Section and our Forensic Identification Services team,” he said. “They have worked tirelessly on this case over the last 19 years.”

He also thanked the Hamilton Police Service, the Centre of Forensic Sciences, Mobile Support and Othram Inc. for their assistance.

Describing Santos as a young working man with his future ahead of him, Smith said the arrest marks an important step toward justice.

“While nothing will ever bring Patrick back, today we can say that the person we allege to be responsible for taking his life has been identified, arrested, and will now have to answer for his crimes before the courts,” he said.

Anyone with information about the homicide is asked to contact the Toronto Police Homicide and Missing Persons Unit at 416-808-7400 or Crime Stoppers anonymously.