The mothers of two young men murdered in downtown Toronto nine days ago made a tearful plea on Sunday for witnesses to help police catch the killer.

"We are asking, pleading, begging, that anyone who has any information that can help find who committed this brutal crime to come forward," Karen Ellis, the mother of Dylan Ellis, said at a news conference on Sunday.

"Somewhere out on the streets of Toronto the person who did this is still around. They're capable of more violence."

Ellis urged the community not to be defined by the tragedy, and said both victims' families believe that Toronto is still a good and safe city.

"It's in this belief and hope that the communities within our city would not accept such a violent and senseless end to the lives of two young men who only shone every day with a brighter light," she said.

Susan Martin, the mother of Oliver Martin, said her son loved Toronto.

"It was his city. He loved people. His favourite saying was, 'Never look down on anybody, unless you're helping them up,'" she said.

Martin said her son felt happy, alive and safe, and his life was ended when he was "shot in the heart."

"I know there are people out there with information. They must come forward."

It was the first time family members of the victims spoke to the media since the killings on June 13.

Dylan and Oliver, both 25, were shot dead while sitting in Ellis' parked SUV. They were attacked after leaving a friend's house. Oliver's girlfriend was in the back of the vehicle but wasn't injured.

Some residents said they saw a man flee the crime scene on a bicycle.

Police have ruled out carjacking and drugs as motives, but say the men may have been involved in a verbal exchange with their killer that fuelled the incident.

Hundreds of mourners attended the victims' funerals in Rosedale on Wednesday and Thursday.

Family members joined the mothers during their appeal on Sunday, crying and consoling each other.

Both victims were described as being full of life and having many loving friends.

Det. Sgt. Gary Giroux told reporters the mothers asked to come before reporters and get their message out to the community.

Homicide investigators, meanwhile, are still receiving tips from residents who live near the crime scene, but Giroux said he couldn't comment on the nature of the phone calls.

Anyone with information is asked to call police at 416-808-7400, or Crime Stoppers anonymously at 1-800-222-TIPS (8477).