Butler police are searching for the gunman who opened fire Tuesday evening at a Butler house with two people inside.

No one was hit by the hail of bullets shortly after 5:30 p.m. but a 30-year-old woman in the home at 313 Wagner Ave. was struck in the back of her head by flying glass, authorities said.

She was treated at Butler Memorial Hospital and released a short time later.

“We believe we have a suspect but no charges have been filed,” Butler police Capt. David Dalcamo said this morning.

Dalcamo would not identify the suspect and declined to provide any more information about him.

Investigators did not immediately know what triggered the shooting.

“A motive has not been determined at this time,” Dalcamo said.

He said the woman and a man who were in the home do not live there. Police did not release their identities. Both have been interviewed, Dalcamo said, and are cooperating with police.

Several neighbors reported hearing an argument or some kind of commotion at or near the house moments before the first shots rang out.

“He was pounding on the door,” a 24-year-old woman said of the suspect. “He was just banging. He didn’t say anything.”

She knew the gunman only by his first name and had seen him previously going in and out of the house.

The woman, who did not want to be identified, lives in a next-door duplex. She was on her back porch with her 2-year-old son when the shots began.

A 29-year-old man who was visiting at the duplex also recounted that the suspect said nothing as he fired the pistol.

“I saw the guy raise the gun and start shooting,” said the man, who did not want his name used. “He shot first at the front of the house and then walked around it, shooting.

“He left in back after he was done. He walked away. He didn’t say a word the whole time.”

The witness did not know the gunman’s name but he had seen him in the neighborhood before.

State police and their forensic services unit assisted city police to process the crime scene, including taking photographs.

Investigators said eight shell casings were collected. They believe those spent rounds came from the shooter.

Police did not disclose the caliber of the rounds. All of them hit the targeted house.

Bullet holes were visible in the yellow siding of the home. To the south, the next-door house had collateral damage.

Two of the shots that went into the home at 313 Wagner Ave., passed through it, striking but not penetrating the other house at 311 Wagner Ave.

Police did not know if anyone was in the other house at the time.

People throughout the neighborhood heard an initial series of shots, maybe two or three, followed by a second volley of as many as six shots.

Yvonne Mazurek was doing the dishes in the kitchen of her home in the 400 block of West Brady Street when the gunfire erupted.

“I was by my window and heard two shots,” she said. “I saw people next door running. Then I heard four more shots. It was right behind my house, almost in my back yard.

“I couldn’t believe it.”

Rick Morrison, who only recently moved to the neighborhood, was on the living room couch watching a college basketball game on television when the gunfire broke out.

“I thought it was fireworks,” he said. He didn’t pay much attention to it.

“I heard, ‘crack, crack,’” Morrison recalled. “I kind of looked up and put my head down again.”

Like his neighbors, he described a brief pause between the barrage of gunfire.

“The first time it was like three shots,” he said. “The second time, probably five or six.”

Dalcamo said the search for the gunman and the investigation continue.

“We’re conducting more interviews,” he said, “and we hope to have this resolved in a very short period of time.”

Meanwhile, city police acknowledged they previously had been called to the house at 313 Wagner Ave. The reason for the prior calls, or when police were most recently there before Tuesday’s shooting, was not immediately known.