The mother of a six-year-old boy who was killed by an older child on a reserve in southern Saskatchewan described her son as a "beautiful baby boy" who liked to laugh and play.

Stacey Merk, 39, testified at a coroner's inquest Monday into the death of Lee Bonneau, who was found with head injuries in a wooded area on the Kahkewistahaw reserve in 2013.

Bonneau was in the care of the Ministry of Social Services and was last seen walking with an older boy outside the reserve's recreation complex while his foster mother was playing bingo.

Saskatchewan's children's advocate determined that the 10-year-old boy who killed Bonneau had behavioural issues and probably shouldn't have been in the community unsupervised.

Because he was under 12, he could not be charged under the Youth Criminal Justice Act.

Coroner's counsel Sonya Guiboche asked Merk why social workers had intervened in her family. Guiboche said there were concerns about domestic violence in the home.

"Me or David never laid a hand on our son," Merk said.

Merk told the inquest she suffers from depression and has a learning disability. She said Social Services were involved in her life since Bonneau was born.

"They had some concerns about how I was going to be a good mom to Lee," she said.

She added that her son was taken into care after she told a case worker that she wanted to commit suicide. Bonneau was killed two months later.

"I regret it," Merk said, crying. "I don't even remember the whole conversation that day.

"I feel that it wasn't right the way they apprehended my son."

Dave Bonneau, the boy's father, said his arguments with Merk were "no different than the average family."

He added that Social Services ripped his family apart.

"If anything, they wanted to tear it farther apart and they've done a damn good job of it," he said.

Guiboche said the purpose of the inquest is to come up with ways to prevent a similar case in the future.

In a report released last year, Saskatchewan's children's advocate Bob Pringle said the 10-year-old boy who killed Bonneau didn't receive the help he needed.

Pringle said his investigation found nine child protection concerns reported to the Yorkton Tribal Council Child and Family Services, but as far his office could determine, two concerns were never investigated. Investigation on some of the others was delayed by months, he said.

He also said the RCMP had alerted the agency to the boy's behavioural issues. Mounties believed he was involved in a break and enter in May 2011 when a pregnant dog and her unborn pups were killed.

The inquest is set to run for two weeks in Regina.