UNION TWP, Lawrence County — A Slippery Rock area man, a volunteer firefighter and a boy are among the four suspects accused of intentionally setting a vacant house on fire last year.

State police on Monday arrested Brandon M. Hooks, 23, of Slippery Rock Township, Lawrence County; and Darrin R. Haught, 19, and Jamie M. Hooks, 19, both of Union Township on charges of arson and other felonies in the case.

A 15-year-old New Castle area boy, who police did not identify, faces similar charges in Lawrence County juvenile court.

The state police fire marshal’s office in Butler filed the case following an investigation into a fire July 22, 2014, that destroyed a West State Street home.

It did not take long for investigators to suspect the fire was no accident. The house had been unoccupied for several years and there were no utilities hooked up there, authorities said.

According to court documents, police believe the suspects used a lighter and lighter fluid to start the blaze.

Haught, who at the time was an active volunteer firefighter with the Union Township Volunteer Fire Department, left the house but later returned and joined a department fire crew in battling the blaze.

Another firefighter suffered a minor ankle injury in the fire, said Chief Patrick Donofrio Jr. of the Union Township VFD.

The three adult defendants, who are free on nonmonetary bail, face felony charges of arson, conspiracy to commit arson, reckless burning and criminal mischief.

Investigators filed a juvenile complaint against the boy.

Police on Monday also charged Haught in a separate arson case for allegedly setting a fire April 22 at a neighbor’s garage on Miller Avenue. The garage sustained only minimal damage.

“I’m very distraught over the whole situation,” Donofrio told the Butler Eagle after learning of the charges against one of his members. “But one bad apple shouldn’t tarnish the entire department.”

Haught has been a volunteer firefighter with Union Township for about two years. Donofrio said he remains under suspension until both cases are resolved.