ST. JOHN, Mo. — A man has been charged with first-degree murder in a shooting that left one woman dead and two others wounded, including a firefighter, at an Applebee's restaurant in suburban St. Louis, authorities say.

Courtney Demond Washington, 28, of St. Ann, was also charged with two counts of assault and three counts of armed criminal action in the attack at the chain restaurant in St. John, The St. Louis Post-Dispatch reports.

St. John Police Chief Robert Connell said Washington had been a customer and was seated at a table around 9:20 p.m. Monday when he got up and left the restaurant then returned and opened fire.

He shot two women sitting at a table, killing Kimberly Ratliff-Penton, 46, from North County. He then stopped at a booth on the other side of the restaurant and shot off-duty Kinloch firefighter Arlydia Bufford in the head, critically injuring her.

Kinloch Fire Chief Kevin Stewart said Bufford, 20, was eating dinner with co-workers after finishing an EMT class when she was shot. As of Tuesday afternoon, Bufford was in critical but stable condition, he said.

Detectives interviewed Washington Tuesday, but have not identified a motive, Connell said. Washington has no known connection with any of the victims.

"He was just calm and collected altogether, before and during" the shooting, Connell told the newspaper. "We're unsure what the trigger was. We hope he'll decide to talk to us and tell us what was going through his mind."

The rampage was over in minutes. Investigators were studying footage from the restaurant's surveillance cameras.