A second defendant in last year’s murder of Krista Dittmeyer is expected to plead guilty today.

Trevor Ferguson, 24, of Tamworth, N.H., is scheduled to appear in Carroll County Superior Court in Ossipee, N.H., according to the New Hampshire Attorney General’s Office.

Neither the prosecutor nor the defense attorney could be reached for comment Monday.

Ferguson was arrested on a charge of conspiracy to commit robbery after the body of Dittmeyer, a 20-year-old mother from Portland, was retrieved from a snowmaking pond at the Cranmore Mountain Resort in Conway, N.H., on April 27, 2011.

Days earlier, Dittmeyer’s 14-month-old daughter had been found unharmed in Dittmeyer’s car, which was running in the parking lot of a nearby recreation center.

Authorities said Dittmeyer was the victim of a scheme to rob her of drugs and money. Her disappearance prompted an intensive search.

Anthony Papile, 29, of Ossipee, N.H., pleaded guilty to second-degree murder in the case last month. He was sentenced to 50 years to life in prison.

Michael Petelis, 29, also was arrested and charged with conspiracy to commit robbery.

Authorities have said that Petelis arranged for Dittmeyer to come to his apartment before Papile hit her with a club. The two men bound her with duct tape and put her in the trunk of her car before Papile drove to the ski area and put her into the pond, according to authorities.

Ferguson gave the other two men a ride back to Ossipee, where they divided money and drugs they got from Dittmeyer, according to court documents. Ferguson got $20 in gas money, according to the documents.

Staff Writer Ann S. Kim can be contacted at 791-6383 or at: akim@pressherald.com