Toronto has a heavy stack of cold case files. Today, there are 612 unsolved murders in the police database, dating all the way back to 1959.\nMany of the cold cases involve victims of gun violence, which has been an ongoing problem in the city for many years, reports The Toronto Star.*\nEditor's Choice:\nHow Ford & Trudeau Really Feel About Each Other According To A Body Language Expert\nOut of the several-hundred unsolved cases, some are remarkably puzzling and interesting.\nOne of the victims is the child of a prominent Toronto activist whose oldest child was murdered on a separate occasion.\nAnother was at a house party with 100 guests at the time of his murder, and yet, the trail went cold.\nHere are a handful of Toronto's most mysterious cold cases.\nSharmini Anandavel\nAnandavel was 15 years old when she went out on Saturday, June 12, 1999. She was last seen leaving her home at approximately 9:00 a.m.\nIn October 1999, her remains were found buried at Finch East Park. Police have yet to name a suspect.\nToronto Police Service\nHolly Anne Painter\nHolly Anne Painter was murdered in 1995. She disappeared on Monday, June 26, and was last seen in a car with two other individuals.\nEighteen-year-old Painter was never seen again after entering the car and police now believe she is deceased.\nToronto Police Service\nRobert Flagiello\nFlagiello was only 18 years old at the time of his death on November 11, 2009. The Toronto Star describes him as being a victim "in the wrong place at the wrong time."\nFlagiello died ushering his friends to safety during a shooting at a music studio. To this day, Toronto police don't know who took his life.\nToronto Police Service\nTina Picoulas\nNineteen-year-old Tina Picoulas was found inside the Comfort Hotel at 445 Rexdale Boulevard on May 29, 2008, but no one knows how she ended up there.\nShe was alive and suffering from medical trauma when police arrived, but was later pronounced dead. There is still no information about what happened to Picoulas.\nToronto Police Service\nTristan Wright\nTristan Wright died during a house party with 100 other people in attendance, and yet no one knows who killed him.\nHe was 23 years old at the time of his death which took place on February 17, 2008.\nToronto Police Service\nKarim Rashid Ata-Ayi\nAta-Ayi was shot outside his apartment building on Sunday, December 23, 2007, at about 2:30 p.m. He was 29 at the time of his death.\nHe was one of two sons of prominent Toronto activist Patricia Wynter who co-founded United Mothers Opposing Violence Everywhere (UMOVE). Wynter's oldest son was also a victim of a homicide.\nToronto Police Service\nPatricia Lupton\nPatricia Lupton is the oldest Toronto Police Service cold case. Patricia was only 12 when she was discovered in medical distress on the side of the road on Monday, March 9, 1959.\nLupton was pronounced dead on the scene and was last seen alive en route to Kennedy Park Plaza sometime after 5:30 p.m.\nAlmost 60 years later, no one knows what happened to her.\nToronto Police Service\n*Editor's note: This article has been updated.