A Connecticut man shot and killed his girlfriends two teenage children before turning the gun on himself, BuzzFeed News reports.

According to Watertown Police Chief John Gavallas, authorities received a phone call on Tuesday from a woman who "reported to us her live-in boyfriend was armed and had just shot her daughter and son." When they arrived on the scene, police found 42-year-old Paul Ferguson dead in the master bedroom from a self-inflicted gunshot wound.

Authorities then found the woman's daughter, 15-year-old Della Jette, laying on the deck and her son, 16-year-old Sterling Jette Jr., on the floor between the kitchen and living room. Both of the teenagers had gunshot wounds to their chests. They were transferred to a nearby hospital where they succumbed to their injuries.

Police believe that Ferguson shot the teenagers before killing himself. Danielle Jette told the officers that there was an argument between Ferguson and her daughter which stemmed from him smoking in the house. When Della returned from school, she spoke to her mother about Ferguson's indoor smoking. The conversation grew louder, prompting Ferguson—who was in the basement watching television with Sterling—to come upstairs. He reportedly "told the daughter to quiet down and not talk to her mother that way."

As the argument escalated, Ferguson retreated to his bedroom and came back with a Glock handgun. Sterling tried to intervene but Ferguson shot him in the leg. At that point, the mother went downstairs to call 911. While on the phone, she heard another gunshot, which is presumably when Ferguson shot the daughter. He then came back into the house and shot the son in the chest. 

"It's traumatic for the whole community, everyone living in Watertown," Gavallas said of the murders. "They had many friends I'm sure, many classmates, and this is very hard to handle." 

Ferguson was a convicted felon who was previously charged with sexual assault in a spousal relationship. As a result, he was not permitted to have a weapon. Despite this, police found several weapons in the residence but they haven't determined if they were purchased by Ferguson. Ferguson and Jette were in a relationship for two years. He moved into the house two weeks before the murders. There is no indication that the incident was sparked by drugs or alcohol.