One person was killed and five wounded when a suspect allegedly opened fire on a bus leaving Los Angeles, California, Monday.

The Greyhound bus was traveling northbound toward the Bay Area with about 40 passengers when the incident occurred just before 1:30 a.m., according to Fox 2.

Following the incident, the driver parked on the side of the road where the suspect exited the vehicle, leaving the gun inside, California Highway Patrol Sgt. Brian Pennings told the Los Angeles Times.

“The driver of the bus immediately pulled to the right shoulder and somehow — we’re still trying to figure out how this happened — were able to coerce the suspect off of the bus,” he said.

The report continued:

The bus driver then traveled to the next freeway exit, at Grapevine Road, stopping at a Valero gas station to get medical treatment for the passengers. Five passengers were taken to hospitals for treatment. One of the people wounded was flown to an emergency room; the rest were taken by ambulance, Pennings said. A 51-year-old woman from Colombia was pronounced dead at the scene, Pennings said. The ages, genders and conditions of the others who had been shot were not immediately available.

When authorities arrived at the scene, they found the suspect on the highway’s shoulder and took him into custody without incident, according to NBC News.

Passenger Mark Grabban, 29, said he and his girlfriend noticed the man’s appearance right away when he boarded the bus and said he spoke loudly and “incoherently.”

“He was, massive, so tall, I remember before this happened, I noticed he had really big shoes on,” he recalled, adding that when someone asked the man to be quiet, he began to argue with them.

“He was muttering things, about ‘wait till we get to the station,'” Grabban commented.

When he heard the man say, “F— you, f— all of you,” that was when the alleged shooting began.

Grabban continued:

I dove to the floor right to under the seat, I got to my girlfriend, tried to put her head down. I was just waiting for the next shot, I was assuming I was going to get shot. There was a mother with two small girls, who were either four or three, frozen with fear, and I was shaking, telling them to stay down. … I saw the blood on the floor of the aisle. I looked to the woman on the left, and she wasn’t responding, wasn’t moving or anything. She was lifeless. It was horrifying to see. I hadn’t seen anything like it.

Police said the suspect has not yet been identified, and they were working to determine a motive.

“I’ve been on for 25 years and I’ve never seen this happen,” Pennings commented.

In a statement Monday, Greyhound offered its condolences to those involved in the tragedy.