BUTLER TWP — A 28-year-old man was seriously injured by an apparent self-inflicted gunshot wound Tuesday night after police responded to a call of shots fired at the Whitestown Village apartment complex, authorities said.

Moments earlier, the man had opened fire with a pistol while chasing after another man in a parking lot at the complex, Butler Township police said.

In all, at least seven shots were fired, but no one else was injured.

Investigators have not nailed down a motive.

“But we believe it was a domestic shooting,” said township Police Chief John Hays.

The man’s girlfriend was “in the process of moving out,” Hays said.

The woman, believed to be her 20s, was at the man’s apartment when the other man showed up.

Police did not immediately identify the shooter or the two others involved.

A medical helicopter later flew the shooter to a Pittsburgh hospital with a gunshot wound to the head. Authorities said he underwent surgery this morning but his condition was not known.

Police were called around 10:20 p.m., after a 911 call.

“The call was a complaint of shots fired,” said a dispatcher at the Butler County Communications Center.

Hays said the shooting happened outside, near the suspect’s apartment on the second-floor in Building 110.

The other man, who police described as a friend of the suspect’s girlfriend, had driven to the apartment “out of concern” for the woman, Hays said.

“He knew she was moving out,” Hays said of the victim.

When the other man was at or near the apartment, the suspect came out with a semi-automatic handgun, firing. The intended victim ran across a parking lot adjacent to a row of townhouses at the same apartment complex.

Several neighbors, none of whom wanted to give their names, recounted hearing at least three shots, and possibly as many as five, coming from outside, in the parking lot.

Police said the suspect fired “at least six shots.”

One of the rounds hit a car parked in the lot.

Some neighbors couldn’t make out what the noise was, or dismissed it as firecrackers.

“I heard what I thought were pops in the distance,” said a middle-age woman who lives in Building 100, across from the suspect. “I didn’t know what they were.”

A third-floor tenant in Building 110 counted four or five shots.

“I thought, ‘Holy (expletive), those are gunshots,” said the man, in his 20s.

By the time police got there, 10 minutes or so after the volley of shots, the suspect was holed up in his apartment at Building 110. Officers banged on his door, hoping to get him to come out.

“I heard pounding on the door,” said the middle-aged woman across from the apartment. “I was very scared. I stayed in my bedroom, with the door closed.”

The upstairs neighbor could hear the police officers.

“They were yelling, ‘Open the door. Open the door. We just want to talk to you,’” the man said. “They were saying, ‘Just come and talk to us.’”

Hays said the suspect locked himself in the bathroom. The front door, too, was locked.

Five to 10 minutes later, the upstairs neighbor guessed, he heard one last shot. He was standing in the living room.

“At first,” he said. “I thought it was a flash bang, like on TV.”

Little did he know, the bullet round apparently went through the suspect’s ceiling and into his third-floor bathroom floor.

“There’s a bullet hole in my tub,” the man said.

Hays said police believe that shot came from a rifle, fired by the suspect.

The slug traveled through the bath tub and ended in fragments in the tub.

Hays said police recovered several pieces of the bullet.

After the last gunshot, the upstairs neighbor looked outside and saw officers go to their car, retrieve a ballistics shield and return to the suspect’s apartment.

Hays said officers forced in the door and went inside.

“They called for him to come out,” Hays said of the suspect. “They could hear him mumbling.”

A short time later, he opened the bathroom door and came out “with his hands up,” Hays said.

The middle-age woman across the hall found the courage to go to her door and look out the peep hole.

She saw the suspect’s front door was open.

“I could hear (police) saying, ‘Stay with me. Stay with me.’ They were using his name,” she recalled. “They were saying, ‘Stay with me, Mike. Stay with me, Mike.’”

Some of the neighbors in the building and in the nearby townhouses looked outside and saw an ambulance crew carry someone out on a stretcher.

Authorities said the suspect was taken to Butler Memorial Hospital and later flown to an unknown Pittsburgh hospital.

Police recovered the man’s rifle in the bathroom.

Meanwhile, District Judge Lewis Stoughton at 2 a.m. signed a search warrant for the suspect’s apartment, where they expected to find his pistol.