CONCORD, N.H. (Court TV) — Prosecutors said a New Hampshire teen who murdered his sister-in-law and two young nephews was by definition a “mass killer” before a judge sentenced him to decades in prison.
In August, 19-year-old Eric Sweeney pleaded guilty to three counts of second-degree murder and a charge of falsifying physical evidence in the deaths of Kassandra Sweeney and her sons, 4-year-old Benjamin and 23-month-old Mason.
Eric Sweeney, accused of killing his sister-in-law and two young nephews when he was 16, enters court on Friday, Aug. 15, 2025 at Merrimack County Superior Court in Concord, N.H. (Geoff Forester/ Concord Monitor via AP, Pool)
Before handing down his sentence, the judge acknowledged the depth of the family’s loss and what the victims’ lives meant to them, and called Eric’s actions despicable.
The judge emphasized the complicated task of determining whether someone who commits such a horrible crime at a young age will be rehabilitated in the future, saying his sentence gave Eric a very tight and narrow path to redemption in the far future.
Eric was sentenced to 60 years to life in prison, to be served concurrently. The judge said the earliest time he could appear before a parole board is at the age of 70.
At the start of Eric’s sentencing hearing on Friday, Assistant Attorney General Bethany Durand told the judge that by legal definition, Eric is a mass killer and should be sentenced to up to 115 years in prison.
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On Aug. 3, 2022, Police responded to the scene after Sean Sweeney called 911 to report his brother had called him from Kassandra’s phone and said someone had broken into the house and “killed everyone.” Inside the home, police found the bodies of Kassandra and Mason in the dining room. Benjamin’s body was found in the kitchen. Durand said the 4-year-old was wearing a dinosaur costume when he was killed. Each victim died from a single gunshot wound. Durand said the evidence showed Eric killed his nephews before fatally shooting Kassandra.
During an initial police interview, Eric told investigators he was in the basement when he heard a “deep male voice” and gunshots before discovering the victims. He then took Kassandra’s Ford F-150 and left the home without seeking help. Durand said he placed the first call to Sean 17 minutes later, not reaching him until 20 minutes after leaving the scene.
Investigators determined Eric used his brother’s Taurus .40 caliber handgun in the killings and disposed of the firearm on a highway. Investigators said there was no evidence of forced entry or burglary at the home, like Eric had told his brother. No motive has been revealed.
At Eric’s plea hearing, Durand described multiple videos and pictures Kassandra had sent Sean in the minutes leading up to the murders that indicated “the family was having a normal morning.” Those videos were also played in court on Friday.
Eleven family members gave emotional victim impact statements, detailing their grief and how Kassandra “thrived” as a mother to her sons. Kassandra’s mother said, “Benjamin had a smile that would light up a room.” Another family member described Mason as “warmhearted, joyful light.”
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Some family members addressed Eric directly, condemning him to “Hell” and detailing their prolonged suffering for the past three years.
Lauren Prusiner, a defense attorney for Eric, delivered a statement describing the conversations they had with Eric about the victims, saying he “loves them” and speaks about them in the present tense. Prusiner described a childhood filled with abuse and neglect for Eric, including alleged sexual abuse, witnessing drug usage and being forced to beg for food.
WATCH | Defense Says Eric Sweeney is ‘Deeply Damaged’ By Childhood of Abuse
Prusiner described how Sean and Kassandra took Eric in when he was 16 years old as he tried to recover, but said after they moved to the home in Northfield, he “fell into a depression,” and the family dynamic changed. Prusiner said Eric’s brain was “deeply damaged” by his childhood. Mental health experts testified about his multiple mental health diagnoses, including post-traumatic stress disorder.
Defense witness Paul Galasso, who met Eric after the murders, described him as “polite” and said Eric “has deep sadness and remorse.” Galasso promised Eric in court that he’d continue to tutor him in prison.
Prusiner told the court Eric wouldn’t be making a statement because he still couldn’t understand the depth of pain and grief he has caused and the reality of what he has done. Prusiner said, “Eric is not a monster. He committed a monstrous crime.” The defense asked for 40 years to life for each murder count, to be served concurrently, arguing he was a minor at the time of the murders and a chance for redemption.
