BUTLER TWP — One of two troopers who returned fire on a man at a township home on Sunday fatally shot a neighbor who showed up with what appeared to be a handgun at the officer’s house in the same township last year.

It was Trooper Brian Knirnschild’s second officer-involved shooting in nine months. He has been a trooper for a little more than two years.

State police said Knirnschild and Trooper Christopher Cialella fired shots at Samuel L. Wheeler, 24, of Butler Township about 4:50 a.m. Sunday during an armed altercation at his parents’ home on Bessemer Avenue in Lyndora,

The troopers opened fired after Wheeler allegedly aimed a 9 mm rifle and shot at them standing 60 yards away. The suspect’s lone shot missed.

Knirnschild and Cialella combined to fire at least three rounds, one that hit Wheeler in the left hand.

The wounded suspect fled but was quickly arrested. He was taken to a Pittsburgh hospital for treatment. Wheeler faces a list of charges including two counts of attempted homicide.

On June 5, 2014, Knirnschild shot and killed 25-year-old Kristopher A. Barkus when he came to the officer’s home on September Drive with an air-powered pellet gun that closely resembled a pistol.

Before the shooting, investigators said, the off-duty trooper shouted for Barkus to leave. Instead, Barkus, who had just left his home just down the block threatening to jump off a bridge, put the gun to his head.

Knirnschild fired six times, hitting Barkus twice in the stomach. Barkus managed to make it to his brother’s waiting car and the two drove to Butler Memorial Hospital. Barkus died a short time later.

Following an internal police investigation, Butler County District Attorney Richard Goldinger ruled the shooting justifiable and said he would not file criminal charges against Knirnschild.

The trooper, who was placed on paid administrative leave following last year’s shooting, subsequently returned to duty.

Police said Knirnschild and Cialella, in keeping with police policy, are on temporary administrative duty in wake of Sunday’s shooting.

A 2004 graduate of Seneca Valley High School, Knirnschild, 28, graduated from the state police academy in December 2012, the department said.

In 2011, while in the Army Reserve, he returned home following deployment to Iraq as part of Operation Iraqi Freedom and Operation New Dawn.