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.”

A man who was visiting at the neighboring 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.”

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

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