A 28-year-old man is charged with attempted murder and a young boy is in hospital with life-threatening injuries after disappearing from his home in Brampton overnight, police said Thursday.

Peel regional police said the five-year-old was found unconscious Thursday morning near a set of train tracks in Brampton and taken to hospital with unspecified injuries.

Dyon Smart of Brampton was arrested shortly after and is "known to the family" of the boy, Const. Harinder Sohi said.

Smart also is charged with aggravated assault, failing to comply with recognizance and breach of a probation order.

Const. Sarah Patten said Smart has a "previous criminal history," but she could not confirm the specifics.

The boy was listed in life-threatening but stable condition and has been moved to a trauma centre, police said.

Sohi said the boy's mother told police she last saw her son at home around 2 a.m. and woke up to find the front door open and the child gone.

Police were called around 6 a.m. and conducted a grid search of the area around the child's home, discovering the boy just before 7 a.m., investigators said.

"In terms of how and where exactly this all took place, that's still part of our investigation and we're not speaking to that just yet," said Sohi.

He said Smart was arrested just after 8 a.m.

Patten said the force's special victims unit is involved in the investigation.

"It's completely unacceptable that this happened to a child," she said.