A father came home to find his son shot to death in their River Street townhouse on Monday afternoon, Toronto police say.

Det. Doug Dunstan told reporters at the scene that the distraught father ran back out onto the street just as a police cruiser was going by.

"The police officer saw the male, came out, went inside and saw the male lying dead on the floor," he said.

The shooting was called in about 2:20 p.m. Monday at 124 River St., which is just south of Dundas Street and at the eastern edge of Regent Park.

Toronto EMS responded, but they pronounced the victim dead at the scene. Police say an autopsy will be needed to determine how many times the victim was shot.

While police were investigating, an unidentified man barged into the crime scene. Police had to restrain him.

There is no immediate description available of any suspects. No one is in custody, although a number of witnesses have gone to 51 Division's offices to be interviewed by investigators.

With a report from CTV Toronto's Natalie Johnson