A New Hampshire teen confessed to murdering his sister-in-law and two young nephews weeks after penning a chilling letter that read, ‘I do not belong in this family’.
Eric Sweeney, 19, fatally shot Kassandra Sweeney, 25, and her sons, Benjamin, four, and Mason, one, while living at their Northfield home.
He shot his victims execution style with a bullet to the head using his older brother’s gun.
Sweeney initially faced first-degree murder charges and was scheduled to go on trial in September, however accepted a plea deal, admitting guilt to three counts of second-degree murder and one count of falsifying physical evidence.
In June 2022, just two months before the brutal killings, Sweeney took the family’s truck and left behind a harrowing note.
‘I do not belong in this family. All I do is steal and lie and be irresponsible,’ the note read in part, ending with, ‘I love you big bro and sis bye.’
Prosecutors cited the message as an early indication of emotional instability and growing conflict in the home.
Kassandra and her husband, Sean Sweeney, were acting as Eric’s guardians and struggled to manage his behavioral issues, which included lying, stealing, and breaking household rules, Assistant Attorney General Bethany Durand said during the Friday hearing.
Eric Sweeney, 19, fatally shot his 25-year-old sister-in-law, Kassandra Sweeney and her sons, 4-year-old Benjamin and 1-year-old Mason at their family home
Kassandra Sweeney, 25, and her husband, Sean Sweeney, had been acting as Eric’s guardians and were struggling to manage his behavioral issues. Pictured: Kassandra and Sean Sweeney with their two sons, Mason and Benjamin
Police were called to the home twice, once after the stolen truck incident, and again less than two weeks before the fatal shootings, when the couple reported that Sweeney was making ‘strange statements’.
‘The situation had deteriorated to the extent that Sean installed a lock on the door of the master bedroom in order to keep the defendant out of that room,’ Durand told Merrimack County Superior Court.
On the morning of the killings, prosecutors said Kassandra had been recording and sending video clips to her husband of the boys playing and laughing, but just moments later, she and the children were dead.
In one clip, the toddler giggles as a family dog plays with the tail of his brother’s dinosaur costume.
In another, both children wave at a groundhog outside the window, saying ‘Hi, Dada’ to the camera.
‘The family was having a normal morning, with the boys playing and laughing with Kassandra while helping her to create video clips to send to their dad,’ Durand said.
‘There was no indication of any unknown person, intruder or danger inside of their home.’
Investigators discovered a chilling note Sweeney had left when he took the family’s truck without permission two months before the killings. Pictured: The Sweeney home in Northfield, New Hampshire
Sweeney (pictured) had initially faced first-degree murder charges and was scheduled to go on trial in September, however he accepted a plea deal, admitting guilt to three counts of second-degree murder and one count of falsifying physical evidence
Family members sat quietly during the hearing, some wiping away tears (pictured), neither they nor attorneys for either side gave statements after court adjourned
Sweeney initially told police he had been in his basement bedroom when he heard something break upstairs, followed by a man yelling and several loud ‘pops’.
He claimed he went upstairs and discovered the victims on the floor, took Kassandra’s phone and car keys, and left the house. He later called his brother, who contacted law enforcement, NBC10 reported.
Kassandra and Mason were found in the dining room, while Benjamin was discovered in the kitchen, each had been shot once in the head.
Prosecutors said Sweeney used his brother’s handgun, which had been kept in a locked safe under the couple’s bed.
Family members sat quietly, some seen wiping away tears during the emotional hearing Friday.
Sweeney will be sentenced on October 3 where he faces 35 years to life in prison for each second-degree murder charge.