Updated

A man who was set on fire while sitting in his SUV outside a convenience store remained hospitalized in critical condition on Saturday as investigators tried to determine what would have motivated a homeless man suspected in the attack, police said.

The 63-year-old Long Beach man was badly burned on the upper torso in Friday evening. His name was not immediately released.

The man was inside his Toyota SUV in front of a 7-Eleven shortly after 5 p.m. when a homeless man threw a flammable substance inside the car. The car's interior and the man went up in flames in seconds, police Sgt. Aaron Eaton said.

The scene was terrifying, said Shannon Flynn, 16, of Long Beach.

"He was engulfed in flames," she told the Long Beach Press-Telegram (http://bit.ly/154YZuu). "The fire was so big, people were screaming. I just can't believe this happened here."

Robert Linkroum said he was buying a newspaper at the store when he looked up and saw a man "walking on a mission" toward the car and throwing what appeared to be a bottle inside.

"The vehicle went up in flames immediately, just totally engulfed. It was all flames," he said. "It became so hot in 7-Eleven that I moved towards the back of the store because I thought the windows were going to blow."

Eaton said bystanders helped the burning man by trying to pour water on him to douse the flames.

Police arrested Raymond Sean Clark, 38, about a block away. Clark, who is homeless, was booked on suspicion of attempted murder and for two misdemeanor warrants for failing to appear on other charges. He remained jailed Saturday on more than $500,000 bail.

Witnesses said Clark is a panhandler who asked people for change and cigarettes outside the store.

Eaton said the motive for the attack was unclear. There was no indication that the victim and attacker knew each other, he said.