As the Toronto police homicide unit continues its investigation into the deaths of a public health nurse and her two young sons, friends and parents who knew the boys say they are in shock.

Zahra Mohamoud Abdille, 43, Faris Abdille, 13, and Zain Abdille, 8, were found dead inside an East York apartment on Saturday afternoon.

Police have not revealed the cause of their deaths, but investigators continue to probe if the homicides are linked to another incident that prompted the closure of a section of the Don Valley Parkway over the weekend.

Police say a man fell to his death on Saturday. His body was found on the busy highway, forcing the closure of the roadway for several hours.

On Tuesday, friends confirmed to CTV Toronto two undated photos that show the young boys. Both attended the Pat Schulz Child Care Centre for four years.

Workers at the Danforth Avenue daycare say they remember the boys fondly, and that they are devastated by the news.

"You don’t want to believe it … it makes you angry, makes you upset, makes you sad," the daycare's director, Kristi Bovaconti, told CTV Toronto.

The older of the two boys, Faris Abdille, was a student at Westwood Middle School. His classmates say he was as "really nice" and "smart."

"He was a good friend and he was one of those kids that put a smile on your face and he was always just happy," one of Abdille’s friends said.

The Grade 8 student was also a member of his neighbourhood's homework club.

Students and staff members of the local organization held a grief counselling session on Tuesday to help them cope with Abdille's unexpected death.

"He was bubbly, he was happy, he was very engaged, very active," Nawal Albusaid, manager of the Thorncliffe Neighbourhood Officer, said. "That's what really hurt us … his character, his personality … remembering all that."

Abdille's younger brother, Zain Abdille, was a Grade 3 student at William Burgess Elementary School. The parent of one of Zain's friends says he is "shocked" by the news.

Theo Margaritis say he knew both of the boys' parents.

"Both wonderful people," he said. "It's something that no one can really imagine."

With a report from CTV Toronto's Janice Golding