Teen pleads guilty in 2022 Northfield triple homicide

CONCORD — A 19-year-old man, formerly of Northfield and accused of slaying his sister-in-law and two young nephews in 2022, pleaded guilty to three second-degree murder charges and one charge of falsifying evidence in front of a visibly tense courtroom on Friday.

The motive remains unknown as to why Eric Sweeney, who was 16 at the time of the murders, acted the way he did.

Earlier this week, on Aug. 13, Sweeney filed a naked plea in Merrimack County Superior Court for the murder of Kassandra Sweeney, 25, and her two children, Benjamin Sweeney, 4, and Mason Sweeney, 23 months, shot on Aug. 3, 2022, in their Northfield home.

A naked plea is a guilty plea with no negotiations with the prosecution. The Honorable Judge John C. Kissinger Jr. presented questions to Sweeney, confirming his acknowledgement of guilt — and the risk — of accepting a naked plea.

As part of the plea, Sweeney agreed to have no contact with his brother, Sean, the husband and father of the victims, nor the family of the victims, except for his mother. Additionally, he is required to pay restitution in the amount of $29,290.88, and he cannot profit or accept payments in regard to the case.

At 8:55 a.m. on Aug. 15, throngs of family members and friends entered the courtroom as a united front, many holding hands and sobbing throughout the roughly 43-minute hearing.

Prosecutors presented five pieces of evidence against Sweeney, who was escorted into the courtroom wearing a light dress shirt with his hands shackled in front of him, which would have been reviewed at trial.

The evidence paints a picture of a quiet Wednesday morning turned chaotic — and a tense living situation which resulted in marital problems between Sean and Kassandra Sweeney. Since 2019, both Sean and Kassandra had been legal guardians of Eric, although the reasoning as to why is unknown at the time of publication.

In documents accessible on the New Hampshire Judicial Branch website, courts.nh.gov, Eric Sweeney often stashed food in his bedroom, and lied frequently to both Sean and Kassandra. Police were called to the home on multiple occasions.

On Friday in Courtroom 1, the state briefly presented evidence of mismatched ammunition connected with one of the two guns owned by Sean Sweeney. The guns were kept locked in a key-entry gun safe at the 56 Wethersfield Drive home. Sean did not think his brother knew where the guns were kept. 

Autopsies conducted following the investigation indicated each victim died from a single gunshot wound.

“Dr. [Jennie] Duval would testify that her examination of Kassandra’s injuries shows the presence of stippling or burns in her skin from the gunpowder released, which would indicate that she was shot at an intermediate range, with the end of the gun being between 6 to 30 inches from her head," said Assistant Attorney General Bethany Durand.

The gun was originally found, discarded, after an extensive investigation by authorities.

According to a press release from state Attorney General John Formella's office sent late Friday afternoon, “On the charges of Second Degree Murder, Eric Sweeney may be sentenced by the Court up to the maximum allowable sentence for each charge, which is life in prison with the possibility of parole.”

A sentencing hearing is slated for 9 a.m. Friday, Oct. 3, at Merrimack County Superior Court, 5 Court St.