Prince George County via Associated Press
This photo provided by Prince George County shows Prince George County Firefighter/Medic John Ulmshneider. Police are trying to determine why a person opened fire on firefighters who were responding to a call for help at a home in a Maryland suburb of Washington. Ulmshneider was shot and killed while making a welfare check and another remains in serious condition, officials said.

TEMPLE HILLS, Md. (AP) — Police are trying to determine why a person opened fire on firefighters who were responding to a call for help at a home in a Maryland suburb of Washington.

A firefighter was shot and killed while making a welfare check and another remains in serious condition, officials said. John Ulmshneider, 39, died Friday night, according to Prince George's County Police Department spokeswoman Julie Parker. She said Ulmshneider was a 13-year veteran of the department.

Department officials said in a statement that volunteer firefighter Kevin Swain, 19, also was shot, and was in serious condition. He was taken to a trauma center for treatment and is expected to recover.

Firefighters and police had gone to the Temple Hills home after being called by a person concerned the individual inside might be suffering from a medical condition, Prince George's County police Chief Henry P. Stawinski III said at a news conference.

When they arrived on the scene, the person inside was unresponsive, so they decided to force entry, he said. As that was happening, the person inside fired several rounds, striking two firefighters and the person who had initially made the call for a welfare check.

Stawinski said that once officers got into the home, the gunfire stopped. He said no officers fired weapons.

"Will it ever end? God, I hope so," Prince George's Police Chief Henry Stawinski said.

The civilian was not seriously injured, according to the police chief. The person who was inside the home was in custody and cooperating with police, Stawinski said. Their identities were not immediately available.

"The main thing that we ask for the men and women of Prince George's County are your prayers, your thoughts," said Prince George's County Executive Rushern Baker.