Teen Pleads Guilty To Murdering Sister-In-Law And Nephews

By DAMIEN FISHER, InDepthNH

CONCORD — Kassandra Sweeney spent the last morning of her life making videos on her phone of her two sons, Benjamin, 4, and Mason, 23-months to send to her husband, Sean Sweeney.

“I hope these make you laugh,” Kassandra Sweeney, 25, texted to Sean Sweeney on Aug. 3, 2022.

Minutes after she texted her husband for the last time, her brother-in-law Eric Sweeney emerged from the basement and shot Kassandra, Benjamin, and Mason to death, shooting each in the head. On Friday, Eric Sweeney calmly pleaded guilty to three counts of second-degree murder, and one count of falsifying physical evidence.

Eric Sweeney, now 19, walked into the Merrimack County Superior Court in Concord wearing a dress shirt, tie, slacks, and shackles. He sat motionless throughout Assistant Attorney General Bethany Durand’s recitation of the still inexplicable murders. When called on to state his plea by Judge John Kissinger, Eric Sweeney’s voice was clear, assertive, and betrayed no emotion.

The court was filled with grieving members of Kassandra and Sean Sweeney’s family, people also related to the murderer who took the three lives they mourn.

Eric Sweeney was 13 when his older brother Sean Sweeney became his guardian. He lived in Sean and Kassandra Sweeney’s Wethersfield Drive home in Northfield for years, but something drove him to kill those seemingly closest to him.

Durand told Kissinger the brothers had clashed in recent months, with police being called to the home on two different occasions before the murders. Once because Eric Sweeney left the home without permission. The second incident involved Sean and Kassandra’s concern about statements Eric Sweeney had been making. The situation became so tense that Sean Sweeney put a lock on his bedroom door, a lock Kassandra Sweeney regularly failed to use, Durand said.

On the morning of Aug. 3, 2022, Eric Sweeney was able to get the Taurus .40 caliber pistol out of the locked safe Sean Sweeney kept under his bed. One key to the gun safe was kept in the master bedroom, and the other in the family’s Ford F-150 truck.

Eric Sweeney then fired six shots inside the home. Kassandra, Benjamin, and Mason were all shot once in the head, with three other shots apparently missing their targets.

No motive for the murders has yet been offered. After killing Kassandra and the two young boys, Eric Sweeney got in the family truck and drove away. He got onto I-93 south and drove three exits away from Northfield when he started calling and texting Sean Sweeney using Kassandra’s cell phone.

“Help,” Eric Sweeney texted.

Eric Sweeney told his brother he had been in his basement room when he heard a loud deep, male voice in the house followed by several “pops.” He went into the main home to find Kassandra, Benjamin, and Mason dead, he told his brother. Sean Sweeney called 911 and raced from his job back to his home.

“My brother just called me from my wife’s phone and said someone had broken in and killed them all,” Sean Sweeney told the 911 operator.

Sean and Eric Sweeney met up at an intersection close to the home and drove back to Wethersfield Drive. Sean Sweeney went to the home to talk to the police officers already at the scene, but Eric Sweeney stayed at the end of the driveway with the truck.

Soon, Eric Sweeney’s story started to fall apart, according to Durand. Police saw no sign of burglary inside the home, and Eric Sweeney told police he never heard the family dogs, Moose and Daisy, barking at the supposed home invader. A surveillance camera at a neighboring house did not record any strange vehicle entering the dead-end Wethersfield Drive that morning. Finally, police found gun residue on the truck’s steering wheel. Sean Sweeney got the truck months before the murders, and he told police he hadn’t fired his guns in years.

Police used Kassandra Sweeney’s cell phone location data to find the Taurus pistol on the I-93 center median. The pistol was left close to the location where Eric Sweeney called his brother to tell him about the murders.

Eric Sweeney had faced three first-degree murder charges before entering into a naked plea agreement this week. The deal allows Eric Sweeney to plead guilty to the lesser second-degree murder charges, but Eric Sweeney is not getting any deal on the potential sentence. He still faces up to life in prison on each count, and the sentence will be determined at a scheduled Oct. 3 hearing.

When Eric Sweeney faces Kissinger in October, there could possibly be some explanation for his crimes. There’s also likely to be more details offered about the life of the 25-year-old mom who spent her final moments making videos of her sons.

One video showed the boys looking out a window at a groundhog in their yard. One video featured the boys looking at the camera saying “Hi, Dada.” Another video showed Benjamin telling his mom that he loved his little brother Mason. Another video showed Benjamin in a dinosaur costume, making Mason laugh as their dog, Daisy, bit the costume tail.

Durand said the bullet that killed Benjamin went through the hood of that dinosaur costume.

This article first appeared on InDepthNH.org and is republished here under a Creative Commons license.