ROCKLAND — A South Thomaston woman admitted Thursday that she strangled and beat an 83-year-old woman to death last year in the victim’s Owls Head home.

Helen Carver The Courier-Gazette

Sarah Richards, 38, pleaded guilty in a Knox County courtroom to murder and theft for the Feb. 21, 2019, death of Helen Carver. Her sentencing has not been scheduled, but Richards faces a minimum of 25 years in prison.

Assistant Attorney General Leane Zainea said the state and defense have agreed that there would either be a 50-year cap on the sentence or no recommendation. Further talks will be held prior to sentencing.

Richards told Superior Court Justice Bruce Mallonee she was guilty and that the state had enough evidence to convict her if the case had gone to trial.

Zainea said Richards admitted to police she struck Carver in the head with a snow shovel, claiming she did it in self-defense because the Owls Head woman tried to attack her.

In two earlier interviews with Maine State Police detectives, Richards initially said she had gone in the house and when she left, Carver was fine. In a second interview, she claimed Carver was already dead but she tried to perform cardio-pulmonary resuscitation on the woman and then left without notifying anyone. The third interview is when Richards claimed self-defense.

Carver had limited mobility, Zainea pointed out, having a wheelchair on the first floor of her home and one on the second floor.

The state Medical Examiner’s Office determined that Carver died of blunt force trauma to her head and upper body as well as strangulation. The autopsy found broken bones in her neck and several broken vertebrae both on the upper and lower back.

Sarah Richards is led out of the courtroom after pleading not guilty to murder in May. Stephen Betts/The Courier-Gazette

The Knox County Sheriff’s Office had been investigating Richards for stealing a debit card belonging to Carver and spending more than $1,000 from the woman’s bank account. Richards had been shoveling snow for Carver. The sheriff’s office had scheduled an interview with Richards for Feb. 22, 2019, on the theft.

On the day of the murder, Richards, her boyfriend and her son were shoveling snow at Carver’s house.

Carver’s son Robert Carver had spoken to his mother by telephone at about 11 a.m. on Feb. 21 and his mother said she was having difficulty with Richards over the stolen debit card. His mother had said that the woman was outside shoveling snow at that time.

Carver’s son, who lives in Bath, tried to reach his mother by phone later in the day and after three unsuccessful attempts, he called police shortly after 1 p.m. Police went to the home and found her dead in a pool of blood.

Police stopped Richards the next day and conducted interviews with her. They also interviewed her boyfriend, who said Richards had gone into the house while they were there shoveling and then came out after a short time and made no mention of what occurred inside the house.

Richards was arrested Feb. 22 and then indicted March 5, 2019, by the Knox County grand jury for murder and theft. She has been held since then at the Knox County Jail.

In September 2019, Justice Mallonee ordered that a forensic evaluation on Richards be conducted to determine her mental competency. Richards initially pleaded not guilty by reason of insanity.

Results of the forensic examination were not released nor discussed at the plea hearing on Thursday.

Carver and her husband, Robert, who predeceased her, operated Carver’s Market in Thomaston – which was at the intersection of Main and Beechwood streets – from 1977 to 1989.

Richards has a long criminal record, including under her former married name, Sarah Stalcup. She was convicted of stealing more than 100 lobster crates from Fox Island Lobster in Cushing in 2013. She had worked at the business.

She received a nine-month jail term in 2016 for unlawful trafficking in drugs. In June 2017, she was sentenced to 30 days in jail for violating her probation for the prior drug conviction.

She was charged with theft in 2012 by Waldoboro police. In 2013, she served seven days in jail for violating a condition of release.

In 2006, Richards was sentenced to five days in jail for violating probation for illegal importation of drugs. In 2004, she was sentenced to 48 hours in jail for theft.

At Thursday’s plea hearing, defense attorney Jeremy Pratt sat 6 feet from his client. Pratt and Zainea both wore gloves in the courtroom for the hearing, which was attended by only Richards, Mallonee, Pratt, Zainea, a court clerk, court officer, a corrections officer, and a reporter.