FARMINGTON — The last co-defendant in a drug-overdose case pleaded guilty Friday to furnishing morphine and falsifying physical evidence related to the death of Marilyn Rider, 52, of Farmington in November 2012.

Eric Barnes, 28, of Skowhegan, formerly of Industry, pleaded guilty to the felony drug charge and the misdemeanor falsifying evidence charge in the Franklin County Superior Courthouse.

A violation of condition of release charge was dismissed in a plea agreement with the state.

Barnes had asked for a bench trial before a judge in September but changed his mind.

He is one of five co-defendants in the case of Rider’s death, which occurred after her birthday party at her home at 103 Silver Maple Lane.

The others are Seth Gordon, 23, his father, Roy Gordon, 42, Terry Oliver, 54, and Scott Kidder, 32, all of Wilton.

A medical examiner would have testified that toxicology results showed Rider’s body had a high level of morphine in her blood, Assistant District Attorney James Andrews told the court in another co-defendant’s case in September.

In regards to Barnes, if the case had gone to trial, the court would have heard evidence that Farmington police Sgt. Edward Hastings IV and other police responded to a report of an unattended death at Rider’s residence on Nov. 11, 2012.

Testimony would have been that during the investigation, police discovered items used to cook drugs, mainly morphine, and inject it intravenously, in a box in a vehicle at the residence. Testimony would also show that when police interviewed Barnes on Feb. 14, he told police he injected morphine into Rider, Andrews said.

Barnes’ attorney, David Sanders, said the court needs to know there was difficulty listening to a taped interview with Barnes and others in the case that was garbled in places.

Sanders said that in a part that could be heard, Barnes said he prepared the solution. He also said he had injected Rider at another time.

It was “Mr. Gordon” who injected Rider, Sanders said. He did not specify which Gordon he was speaking about.

From the police perspective and the police reports he read, Andrews said that Barnes is one of the people who injected Rider.

Barnes said he was talking about setting up the drug for injection on the tape.

Either action fits the charge, Andrews said.

In Seth Gordon’s case, Andrews said in September that testimony would show that he assisted in injecting Rider intravenously with the morphine.

The plea agreement for Barnes and Seth and Roy Gordon, who was Rider’s boyfriend, calls for a two-year sentencing cap. The conviction on the felony carries a penalty of up to five years in prison.

The Gordons each pleaded guilty in September to a felony charge of unlawful furnishing of a schedule drug.

Justice Michaela Murphy asked Barnes if he understood that the court could impose a five-year sentence and suspend all but the two years.

The most prison time she could impose under the agreement is two years, she told him.

Barnes said he understood.

Murphy said she will consult with the other defendants’ lawyers to see if 1 p.m.  Nov. 14 would be good for sentencing for the four co-defendants.

Oliver is also expected to be sentenced in November. She pleaded guilty in May to a felony charge of unlawful trafficking in scheduled drugs. She sold her morphine pills to the co-defendants, according to testimony in the case.

Kidder pleaded guilty in March to furnishing morphine. He received a three-year suspended sentence and two years of probation. He was serving a sentence on another conviction at the time.

dperry@sunjournal.com