The parents of one of the slain teens who were killed in a brazen daytime shooting in Etobicoke say they brought their only child to Canada more than 10 years ago in hopes of giving him a better life.

Zaid Yousif died Monday during a lunchtime shooting. The 17-year-old -- who came to Canada from Iraq in 2003 -- was a student at Don Bosco Catholic Secondary, located near Islington Avenue and Dixon Road, not far from where the shooting occurred.

Fifteen-year-old Michael Menjivar was the second victim. He was a student at James Cardinal McGuigan Catholic high school, located near Keele Street and Finch Avenue.

Yousif's parents say their son was a "good boy" who rarely made them angry.

"We came to Canada to look for a better life for our kid," father Athir Yousif told CTV Toronto on Tuesday. He and his wife celebrated their son's 17th birthday over the weekend.

Police have detained and released at least one person of interest and continue to search for at least three other suspects. Surveillance camera images taken near the scene of the shooting show there were a number of witnesses at the time of the incident.

Police say they may release those images on Wednesday, which also show persons of interests in connection with the case.

Monday's double shooting happened outside of the Toronto District School Board's School of Experiential Education, on McArthur Street across from Don Bosco, at approximately 12:30 p.m. on Monday.

In a statement Tuesday afternoon, police said homicide investigators have taken over the investigation.

Angela Gauthier, director of education for the Toronto Catholic District School Board, said police are offering support to students and teachers dealing with grief. Counsellors and social workers were also at both high schools Tuesday morning and will remain there as long as they are needed, Gauthier said in a statement.

"The thoughts and prayers of our entire school board are with the families of these two young men as we mourn their tragic loss," she said.

"There are no words to adequately express our shock and sorrow at such an event taking place in our city. As educators, we all work diligently to ensure that our students feel safe at all times."

Gauthier also said the school board will eventually conduct an analysis to determine if there was anything it could have done to prevent the shooting.

Police spent the morning combing the scene and nearby apartment buildings for evidence.

Post-mortem examinations were also being conducted on both victims.

Supt. Ron Taverner said police believe the shooting may have been a "targeted" incident but that the investigation was still in the preliminary stages.

"Obviously it is of great deal of concern that there are people out there with firearms that use them….We are working on trying to bring those individuals into custody," Taverner told reporters Monday afternoon.

Anyone with more information is asked to call police at 416-808-2222.

With a report from CTV Toronto's Austin Delaney, John Musselman and Janice Golding