Montreal police are looking for a possible witness who they say was in des Bateliers Park on the day 10-year-old Ariel Jeffrey Kouakou disappeared on the morning of March 12.

Police say the woman was sitting by the shore of the Rivière des Prairies smoking a cigarette between 11 and 11:30 a.m.

Police are now asking that the woman come forward with any information.

Insp. Ian Lafrenière, head of police communications, said the woman is not a suspect, but police would like to know if she saw anything that morning that could assist police in their ongoing search.

"We don't even know if that woman saw something, but we would love to talk to her," said Lafrenière.

"We don't believe that person is going to help us find Ariel, but at least we can get some details of what was going on before the loss of Ariel."

Police have received more than 400 tips since Ariel disappeared. From those tips, police learned of the possible witness, he said, but they do not have a detailed description of the woman.

The woman is encouraged to stop by a police station to speak with officers or even call 911, he said.

Police divers have repeatedly searched Rivière des Prairies since he disappeared in March. (Ryan Remiorz/The Canadian Press)

Ariel disappeared after he left his home in Montreal's north-end borough of Ahuntsic-Cartierville to meet a friend. He was last seen in des Bateliers Park, which is about two minutes from his home.

Ariel is about four-foot-seven, and weighs 88 pounds.

Divers have repeatedly searched the river for Kouakou's body. They conducted a search most recently as two weeks ago, but, Lafrenière said, nothing was found.