Police are treating the death of a Nova Scotia woman who fought for compensation for residential school victims as suspicious, but members of the Mi'kmaq elder's family say she died of natural causes.

Nora Bernard's son called 911 shortly before 3 a.m. Thursday after finding his mother on the floor of her Truro-area home, Leanna MacLeod told CBC News.

MacLeod, Bernard's daughter, said Truro police took her brother into custody for questioning but released him a few hours later.

MacLeod is upset with how police are handling her mother's death and said Bernard, who had triple bypass surgery, died of a heart attack.

As of late Thursday afternoon, investigators were treating the house as a potential crime scene.

Police were saying little about Bernard's death.

"Any time the manner or cause of death is not apparent, then certainly it's suspicious," Sgt. Randy MacKenzie said earlier Thursday.

Bernard was recently awarded about $12,000 in compensation after a long battle on behalf of 80,000 residential school survivors across Canada.