The mother of a young man killed in what police believe was a random shooting in Toronto's northwest end pleaded for her son's killers to turn themselves in Tuesday.

"You have to go and give up yourself to the police. Surrender yourself to the police and tell us why," Margaret Nwosu said in an interview with CTV News Toronto from her Toronto home, four days after 26-year-old Nnamdi Ogba was killed.

Ogba, who lived in Brampton, had been visiting a soccer teammate on Scarlettwood Court and was walking to his car just after 11 p.m. on March 16 when two men approached from behind and shot him several times in the back.

Toronto Police Homicide Det. Jason Shankaran said Monday he doesn't believe Nnambdi knew his killers or had had any interaction with them before the shooting.

"Mr. Ogba did nothing to bring this onto himself," Shankaran said. "The only thing that led to his death was simply walking out of that building at that particular time and place and having these two individuals meet with him in that parking lot."

Ogba, the eldest of five children, immigrated to Canada from Nigeria nearly a decade ago as a teenager. Seeing Canada as a land of opportunities, he wanted to work immediately, his mother said, but she insisted that he go to school and get a proper job before being "released" into the world as a man.

And he did just that. He went to high school. He went to Seneca College. He became an electrical engineer, being selected for a job at Continental Studwelding before he even graduated, his mother said.

"Nnamdi was a good boy, very gentle, very respectful. Everybody around (who) knows him knows that he's a very respectful and very responsible boy," Nwosu said. "He was a role model, just 26 years old."

Surveillance video released by police shows two young men climbing out of the passenger side of what is believed to be a newer model Nissan Rogue before walking through the housing complex. The video shows Ogba walking to his car before the two men apparently notice him and walk up from behind. Police say Ogba was shot several times in the back.

He had been planning on picking up African food before going to visit his fiancée, according to police.

Ogba's mother said he planned to marry this year. His fiancée was too upset to speak publicly Tuesday.

Community leader Chinedu Okoro said the Nigerian community is "astounded by the news."

"A brilliant young man, the cream of the crop, the best among us has been taken from us and we are saddened," Okoro said. "And I don't know why anyone would want his life."

Ogba's family is planning a vigil for him at the scene on Scarlettwood Court from 7-8 p.m. on Friday.