Police confirmed the violent deaths of three people Tuesday night in Watertown, Connecticut.

Paul W. Ferguson, 42, shot and killed his girlfriend’s teenage son and daughter before turning the gun on himself. Sterling Jette Jr., 16, and Della Jette, 15, were found suffering from their wounds by police and were later pronounced dead at Waterbury Hospital.

The mother, Danielle Jette, was unharmed. She called police after the shooting occurred at about 9:45 p.m. When authorities arrived at the home, Ferguson was pronounced dead at the scene.

The shooting reportedly resulted from an argument Della Jette was having with Ferguson over his smoking in the house. Ferguson retrieved his Glock handgun, prompting the brother to interject himself into the conflict.

Ferguson first shot Sterling Jette in the leg, prompting Danielle Jette to find her phone and call the police. According to Danielle Jette’s testimony, she then heard Ferguson shoot her daughter in the chest on the back porch before returning to shoot her soon again in the chest. Ferguson then locked himself in another room and shot himself.

According to police, Ferguson had a prior felony conviction and should not have been in possession of a gun. His case had initially been for spousal sexual assault but his charge was pleaded down to unlawful restraint. He had moved into the home of Danielle Jette and her children in mid-November. Ferguson and Danielle Jette had been dating for about two years, according to the Hartford Courant.

“Our hearts go out to the students' family and friends during this difficult time," said Kerry Markey, director of communications for Connecticut Technical Education and Career System. “There is nothing worse that can happen to a school community. Our number one priority right now is doing all we can to support our students, staff and families through this crisis.”

Both Sterling and Della Jette attended W.F. Kaynor Technical School and the family was said to be very close with their community.

crime scene
Representational image Getty Images/Jonathan Alcorn