Something terrible happened in a quiet apartment building at 5005 Dundas St. West on Saturday night. But where one tragic mystery ends, another equally bizarre puzzle begins and it has Toronto Police desperately searching for two people who may know a lot about a murder - or may have been victims themselves.

The drama began when the lifeless body of 20-year-old Jamie Hilton was discovered near the elevator of the residence in the Islington and Dundas St. area. A second man, who wasn't as badly hurt, was taken to hospital. Cops identified an apartment as the crime scene. But the whereabouts of the couple who lived there is unknown.

Now they're hunting the pair, believed to be in their 40s. They're unsure if they're merely terrified witnesses who are afraid to come forward and finger a violent killer or two more victims of the same attacker. Cops are only sure of one thing at this point - they're apparently not suspects and they don't think they had anything to do with what happened inside their home.

"Our information is that there was a man and a woman who occupy that apartment and in fact were present during the shooting," explains Det. Sgt. Steve Ryan. "We went back and found the crime, [but] they were gone. It appeared that they just up and left. So first and foremost, I want to make sure that they are in fact safe and that they weren't victims of some sort of violence or some sort of crime themselves. So what I'm hoping is that they themselves, or anyone who knows them, would call us."

For other residents of the address, the now blood stained hallway is a bitter sign of ongoing troubles. "There's problems in our building," Emily Greene laments. "There's entrances to our building that are propped open a lot, locks are busted in. We've got people sleeping in our stairwells and it's just -- it was scary."

Police say Hilton, who lived with his mother in a nearby building, didn't have a criminal record. He was remembered by his uncle as a good boy. "Our landlord got a phone call last night at my house saying he has been shot," a saddened Denzel Reid relates. "So I just go buy some flowers. Me and my friend will lay it outside here, that's all."

Hilton's death brings to 71 the number of homicides in this city in 2007 - that's two more than in all of 2006 and not far away from the record of 88 homicides Toronto had back in 1991.

The names of the missing couple haven't been released but if you know them or know where they are, call Crime Stoppers anonymously at 1-800-222-TIPS (8477).

Annual homicide totals for each year this decade:

2000: 61
2001: 61
2002: 62
2003: 67
2004: 64
2005: 80
2006: 69
2007: 71