Dozens of stuffed animals and flower bouquets mark a makeshift memorial for two children who died in Winnipeg on Wednesday. Winnipeg police continue the look for their mother, Lisa Gibson 32, who they said is a person of interest.

It’s believed the toddler and infant drowned in a bathtub in their Westwood home on Coleridge Park Drive on July 24. They were rushed to hospital but couldn’t be revived.

Neighbours brought teddy bears and flowers to the Coleridge site Wednesday and into Thursday.

Tony Colbourn’s grandkids knew two-year-old Anna and three-month-old Nicholas from playing out in the yard.

“They’ve asked and it’s very delicate to answer these questions because obviously they can’t understand why children are gone,” he said.

Winnipeg police said they’re concerned for the well-being of Lisa Gibson.

“We’re still treating this as we’re searching for Ms. Gibson alive. We have no indication at this time to think otherwise,” said Const. Eric Hofley.

River patrol and dive units were cruising up the Assiniboine River near the Gibson’s home Thursday, along with the police helicopter being spotted in the air above.

Police search and rescue officers were going door to door in the Westwood area. Victims services staff were also going through the neighbourhood.

While some neighbours said the mother of two had been dealing with postpartum depression, police will not comment on her health.

“She looked (like) a very, very good mom,” said Colbourn.

“It just breaks my heart that this happened anywhere, let alone so close to home,” said neighbour Jane Klassen. “We saw them in the street all the time, the little girl playing, and it’s just very sad.”

The community is coming together to support each other during the tragedy.

“If anything, it makes you feel like you need to be more open to the people around you and what they’re going through,” said Klassen.

Police said they’ve received several tips. Anyone with information on Lisa Gibson's location is asked to call investigators at 204-986-6508 or Crime Stoppers at 204-786-8477.

A vigil for the Gibson family was also held at 7 p.m. July 25 at Winnipeg Mennonite Elementary, 250 Bedson Street.

- with a report from Alesia Fieldberg