Investigators said they had a person of interest in the boy's death, but stopped short of labeling the person a suspect, the Canadian Broadcasting Corp. reported. The nature of the boy's fatal injury wasn't disclosed by police.
Emergency crews were called to a home about 5:30 a.m. CST and the child was pronounced dead at the scene. Three other people were in the residence when officers arrived.
"We have a tragedy here," Alyson Edwards of the Saskatoon police told reporters Saturday afternoon. "We are doing our best to try and get some answers."
"It's hard for our officers to deal with. I can't imagine what it is like for the family. Any type of homicide is tragic, but when you're dealing with a small child, 5 years old, it's awful."