Police divers are combing the icy waters of a river that runs along a rural property in Laval, Que., where a young autistic boy went missing on the weekend.

Adam Benhamama was last seen playing with his sister on Sunday afternoon, on a waterfront property on the Mille Iles River.

The three-year-old slipped out of sight and his sister quickly reported him missing.

The family called police who brought in dogs, ATVs and more than two dozen officers to assist in the search for Benhamama, who is unable to speak or hear.

CTV Montreal's Cindy Sherwin said Benhamama's father had brought him and his sister to the property to visit a family friend.

The boy's mother wasn't with them, but she went into shock when she got a telephone call telling her that her young son was nowhere to be found.

As night fell, there was no sign of the missing boy. A day later, there are growing fears that Benhamama may not have been able to survive a long, cold night in the woods.

"They are growing very, very concerned that they may not find this little boy alive," said Sherwin, reporting from the edge of the property where Benhamama was last seen.

Laval police spokesperson Nathalie Lorrain said police will continue to search the property, its wooded area and the nearby river where divers have been deployed.

"Unfortunately, we're thinking more and more that the little boy may have fallen into the river in the back of the house," Lorrain said Monday.

Even if the boy is alive, the search is a difficult one: Lorrain said Benhamama's inability to speak or hear means that "he can't cry out for help and even if we scream for him, he cannot hear us."

Benhamama has dark hair and was wearing a black jacket, blue jeans and a striped toque when he went missing. He is two feet tall and weighs 25 pounds.

Police are asking members of the public to approach the missing boy gently if they see him and to contact authorities as quickly as possible.

With files from The Canadian Press