Sarah Richards, 37, of South Thomaston enters the courtroom with her attorney Jeremy Pratt at the Knox County Superiour Court in Rockland, Feb. 25, 2019. Credit: Gabor Degre

The South Thomaston woman accused of killing an elderly woman last month allegedly told police she killed the woman after they had an altercation about a stolen debit card.

Sarah Richard s , 37, has been charged with murder and theft since the Feb. 21 death of Helen Carver, 83, of Owls Head. Carver, who lived alone, was found dead in her home by one of her sons. Richards has been held without bail since her Feb. 22 arrest.

A Maine State Police affidavit filed in Knox County Superior Court was unsealed Thursday, detailing what police believe occurred leading up to Carver’s death.

[Slain Owls Head woman ‘did not deserve this,’ son says]

Richards had been shoveling Carver’s walkways and driveway since December. On Feb. 14, one week before her death, Carver told the Knox County Sheriff’s Office that she believed Richards had stolen her debit card, according to the affidavit.

After the initial theft report, the sheriff’s office obtained “multiple videos” of Richards allegedly using Carver’s debit card, Maine State Police detective Scott Quintero wrote in the affidavit.

A sheriff’s deputy contacted Richards and scheduled an interview regarding the theft for Feb. 22, the day after Carver was ultimately killed.

In a phone call around 10:45 a.m. on Feb. 21, Carver told one of her sons “that the woman doing her snow removal had stolen her debit card,” Quintero wrote. About 45 minutes later, witnesses told police they saw Richards and her boyfriend leaving Carver’s home.

[Owls Head woman killed in her home remembered for strong faith]

When located by police on Feb. 22, Richards said she was at Carver’s home for snow removal the previous day. She initially told police that when she left, Carver was “in good shape,” according to the affidavit.

Through further questioning, Richards allegedly admitted that she stole Carver’s debit card and changed her initial story, stating that when she arrived at Carver’s home she was already dead. Richards said “she provided lifesaving efforts and then left,” according to the affidavit.

Richards changed her story a final time, telling police that when she arrived at Carver’s house on Feb. 21 she spoke with Carver, who was upset about Richards allegedly stealing her debit card. Richards said that Carver, who used a wheelchair, “came at her” so she lunged at Carver and tackled her into an entertainment center, according to the affidavit.

[Woman charged in connection with Owls Head death has long criminal record]

Richards then struck Carver in the head “with a tool [she] had brought into the home,” the affidavit stated.

An autopsy conducted on Carver determined that she was killed by blunt force trauma with evidence of strangulation.

Richards is scheduled to appear for her arraignment in Knox County Superior Court on May 23 at 1 p.m.. Richards was indicted by a grand jury earlier this week on the murder and theft charges.

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Richards made her initial court appearance last week, when Superior Court Justice Bruce Mallonee ordered that she remain held without bail. Richards’ attorney Jeremy Pratt did not request a bail hearing.

Richards has a lengthy criminal history, consisting mostly of thefts and drug convictions. Most recently, Richards was convicted in 2015 of stealing and reselling lobster crates with her then-husband from the Fox Island Lobster Co. Richards was sentenced to serve 10 months at the Maine Correctional Center in Windham and pay $1,605 for her role in that crime, according to her criminal record.

If Richards is found guilty of murder, she faces a minimum sentence of 25 years in prison and a maximum sentence of life in prison.