A gunman who killed a woman and wounded five others on a Greyhound bus in Southern California was cursing and muttering incoherently before the attack, passengers and authorities said.
Investigators are trying to determine a motive for the apparently random assault Monday that left two people in critical condition.
Anthony Devonte Williams, 33, of Capitol Heights, Maryland, was arrested after passengers managed to disarm him and get him off the bus, California Highway Patrol Sgt. Brian Pennings said.
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"There’s no indication that he knew anybody on there," Pennings said.
Williams was booked at the Kern County jail Monday evening on suspicion of murder and attempted murder and was held without bail. It wasn't immediately known whether he had an attorney.
The packed bus was heading from Los Angeles to San Francisco when shots were fired at about 1:30 a.m. Monday on Interstate 5 near the small mountain community of Lebec, about 70 miles (113 kilometers) northwest of Los Angeles.
"As soon as we took off, the shooter was talking really loudly, incoherently, I couldn't really hear much of what he was saying...," witness Mark Grabban told NBC News. "At one point he got in a verbal dispute with one of the passengers who asked him to quiet down. It was in Spanish, but to the effect of trying to get him to quiet down."
"A passenger behind him [the gunman] stood up, and he stood up at the same time. He told the passenger to sit down, I heard ‘f--- you, f--- all of you,’ and I heard a gun cock, and 8 to nine rounds let off," Grabban recalled.
"Numerous" passengers on the bus called 911 to report the active shooter situation, officials said.
The driver pulled to the shoulder of the freeway, where authorities said some passengers managed to get Williams off the bus.
"Due to some very heroic acts by the passengers, they were able to overcome this subject and disarm him," Pennings said. "They were able to escort him off of the bus."
He didn't provide details.
Passengers told Grabban someone wrestled the gun away from the shooter, but he didn't witness it, he said.
Williams left the weapon -- a semi-automatic 9 mm pistol and several extra magazines -- on the bus, Pennings added.
Highway patrol officers found Williams a few minutes later and detained him.
"This is extremely rare ... I'm not aware of this ever happening," Pennings said of the deadly bus shooting.
The driver and 42 passengers were aboard, including 6- and 8-year-old children who were not hurt.
A 51-year-old woman from Colombia, based on her passport, was killed. Her name wasn't immediately released, Pennings said.
A 45-year-old man and a 19-year-old woman were hospitalized in critical condition, a 39-year-old woman had major injuries, a 49-year-old man had moderate injuries and a 50-year-old woman had minor injuries, Pennings said.
Witnesses and passengers were interviewed, along with the suspected shooter, authorities said.
The remaining passengers were later driven to Northern California on another bus, but some
"You need to implement proper security measures at ALL of your stations! A bus departing from Los Angeles had been infiltrated by someone with a gun, and we are currently stopped at the Grapevine to have authorities and paramedics assist with the shooter situation!" one passenger aboard the bus tweeted to Greyhound.
Authorities were looking into whether a video camera aboard the vehicle captured the attack when the bus was at the top of Tejon Pass. It rises to an elevation of more than 4,100 feet (1,250 meters) in Lebec.
"Our thoughts and prayers go out to everyone and every family member impacted by the incident today," Greyhound said in a statement to NBCLA. "We are gathering details and will assist the Kern County police in every way possible during their investigation."
Greyhound prohibits passengers from bringing guns, explosives or dangerous chemicals on board its buses or in their luggage, according to its website. The company declined to answer additional questions about security on its buses.