ALBUQUERQUE, NM (AP) A gunman opened fire at an Albuquerque fiber optics manufacturer on Monday, killing two people and wounding four others before turning the gun on himself in what police said was a domestic violence dispute.

Earlier Monday, police Chief Ray Schultz said there were six dead.

He explained at a news conference later that responding officers had seen people down and believed they were dead, then continued into the building to search for the gunman. Officers who arrived later determined several shooting victims had survived.

Schultz also said there was confusion at University of New Mexico hospital, where one victim died but was reported as two deaths.

The shooting at Emcore Corp. appeared to involve the 37-year-old gunman’s ex-wife or girlfriend, police Chief Ray Schultz said. It was not immediately clear whether she was among the dead, or what caliber weapon he used.

“In a situation like this, there are other people in the building and they became, unfortunately, casualties as well,” he said.

Schultz said the gunman was a former employee, but did not release his name.

Chaos unfolded as the gunman opened fire, sending employees fleeing for cover as police locked down the entire neighborhood. Police were alerted to the shooting shortly before 9:30 a.m. Five officers were inside the building within three minutes, Schultz said.

Police locked down the city’s southeast side as a precaution but Schultz said authorities don’t believe there was a second gunman.

Schultz said the gunman had children who live outside Albuquerque and said they were taken into custody by “another agency.”

The chief said there was at least one previous domestic violence call involving the gunman but said it occurred outside Albuquerque. He did not say where.

Police said 85 employees were later taken to a community center for interviews with detectives.

Emcore manufactures components that allow voice, video and data transmission over fiber optic lines. They also manufacture solar power systems for satellite and ground-based systems.

Based in Albuquerque, the company has about 700 full-time employees.