NEWPORT — After suffering a heart attack following hip replacement surgery, Anna Richard was enjoying her first day out of the house with a shopping trip to Claremont in late August.

The 93-year-old Washington, N.H., resident drove to Market Basket on the afternoon of Aug. 27 and completed her food shopping with ease.

“Everything was so great,” she recalled in an interview outside of the Sullivan Superior courtroom on Thursday.

A 41-year-old woman from Vermont even helped load her groceries into the car. But the day quickly took a turn for the worse when the same woman hit Richard in the back, pushed her up against the car and stole her purse.

Richard’s assailant, Heather Deem, of Mount Holly, Vt., pleaded guilty to a felony charge of conspiracy to commit robbery in the Newport courthouse on Thursday. Judge Brian Tucker sentenced her to serve at least 18 months in the N.H. State Prison for Women.

An emotional Deem expressed remorse for her actions. She turned and faced Richard in the courtroom and, through sobs, addressed her directly.

“I am very sorry for what I did,” she said. “I do deserve to be punished.”

Deem also told the judge that her helping Richard load groceries into her car was a genuine act.

“I was doing that as a kind person,” Deem said.

Sullivan County Attorney Marc Hathaway saw it differently.

“After that act of kindness, she decided nevertheless to assault this woman and take her purse,” Hathaway said in court.

Deem fled the scene in a car allegedly driven by Jennifer Graham, 37, of Mount Holly, Vt., who is facing a similar charge.

Deem told police Graham came up with the idea to snatch a purse at random to pay off a drug debt; Deem executed the robbery, according to a police affidavit.

In court, Deem told Tucker she has an opiate addiction.

Hathaway asked Tucker to sentence Deem to two to five years in prison, while Deem’s attorney, Jay Buckey, sought 90 days in the house of corrections followed by two years of probation.

Buckey said Deem has a minimal criminal record and is a provider for her two children, who were in the car on the day of the incident. Hathaway balked at the defense’s proposed sentence, calling 90 days “an irresponsible message to send.”

“Addiction does not remove responsibility,” said Hathaway, who called the robbery “the predatory stalking of a 93-year-old woman in a public place to steal her money in order to pay a drug debt with her children in the car.”

Tucker told Deem he believes she is remorseful for what she did but said he must send a “strong statement” that this type of conduct won’t be tolerated.

He formally sentenced her to two to five years in prison, with the ability to have six months of her minimum sentence and one year of her maximum sentence suspended if she successfully completes substance abuse treatment programming in prison. Deem also must pay $125 in restitution to Richard.

Graham’s case is pending.

She plans to take it to trial, Hathaway said on Thursday.

Richard, who was a welder during World War II in the Navy Yard in New York City, said she still has aches in her back and pains in her arm that were caused by someone she thought was a good Samaritan. Fortunately, she was spared serious injury.

After the sentencing, she said she had been upset that Deem turned out to be a purse-snatcher and ruined a sunny summer day back in public.

“For that, I could punch her,” Richard said.