Kassandra Sweeney, 25, a devoted mother and nursing assistant, cherished every moment with her two young sons, Benjamin, four, and Mason, one. On a seemingly normal Wednesday in August 2022, she captured playful videos of the boys — Benjamin in his favorite dinosaur costume — to send to her husband, Sean, who was at work. Minutes later, tragedy struck.
The messages Sean received from his teenage brother, Eric Sweeney, 16 at the time, revealed that someone had killed Kassandra and her children. Eric, who had endured years of abuse and a turbulent upbringing, had been living with Sean and Kassandra since age 13 after they became his legal guardians. Despite their care, Eric’s behavior had become increasingly concerning, prompting Sean to even install a lock on his bedroom door and seek alternatives for Eric’s living arrangements.
Police arriving at the Northfield, New Hampshire home found Kassandra and her sons shot dead. The crime scene showed no forced entry, and investigators realized Eric had taken his actions with chilling awareness, stepping over the bodies to take Kassandra’s phone and car keys. Authorities noted prior reports about Eric constructing weapons and making threatening statements.
In October 2025, Eric, now 19, was sentenced to 60 years to life for the murders. Prosecutors emphasized that despite his traumatic past and young age, the killings were deliberate, senseless, and heinous. His defense argued that Eric’s depression worsened after losing access to therapy and that he could not remember the crimes.
The judge acknowledged the gravity of the murders while noting Eric’s abusive childhood, stating that the sentence allowed a path for potential redemption, despite the immense suffering he caused.
