A 28-year-old man is charged with attempted murder after a 5-year-old boy disappeared from his Brampton, Ont. home and was later found with life-threatening injuries near train tracks.

The suspect, who police say was known to the victim, has been identified as Dyon Smart of Brampton.

Police have not identified the child or his mother, or explained their relationship to the suspect. But neighbours told CTV Toronto that Smart is an ex-boyfriend of the boy’s mother, and he had been staying at the home.

Peel Regional Police say they received a call about the missing child just after 6 a.m. on Thursday morning. He was last seen by his mother in his bedroom at his home at approximately 2 a.m.

The child’s mother woke up around 6 a.m. and discovered he was gone and the door was open, police said.

An hour later, police said a K9 officer found the child close to train tracks not far from his home. The boy was unconscious and showed clear signs of physical trauma, police said.

The boy sustained head injuries and was taken to Brampton Civic Hospital in life-threatening condition, paramedics told CP24. He was later transported to a trauma centre, according to police, who described the boy’s condition as “life-threatening but stable.”

Smart appeared in court Thursday. He is charged with attempted murder, aggravated assault, failure to comply with recognizance and breach of probation order.

Police said there were no signs of forced entry at the home.

“As far as the circumstances of how he went missing or what happened, we don’t know yet," Const. Harinder Sohi said.

“We will be interviewing the mom later on and we’ll be looking for any video in the area and try to speak to witnesses who might have seen what happened.”

The railway tracks where the boy was found have been shut down for the investigation, according to police.

Peel Regional Police Const. Sarah Patten said the area around train tracks is being canvassed and family members are being interviewed.

“This is a huge investigation so it’s going to involve a lot of resources. We’re going to get to the bottom of this as fast as possible. We’re glad that we were able to make the arrest today because of how big of a deal this is,” she said.

Patten added that police are “very happy that the child is considered in stable condition at this point.”

“This is completely unacceptable that this happened to a five-year-old child,” she said.

Michael Cowan, who lives in the area, said news of the little boy’s grave condition has been hard to comprehend.

“Everybody out here loves this little boy. I’m getting kind of torn up…it’s just a sad situation,” Cowan said.

With files from CP24