Two San Diego firefighters were hospitalized with multiple stab wounds a day after a bystander attacked them as they were helping a drunken man on a packed trolley platform Wednesday.

The attacker approached the firefighters at about 4 p.m. as they were responding to a 911 call reporting an intoxicated man who had become ill on the downtown platform, Capt. Joe Amador of the San Diego Fire-Rescue Department said.

"As you can imagine, it was chaos," Amador said

One firefighter was stabbed in the back and both were stabbed more than once. Police and other firefighters rushed to the scene and authorities arrested a suspect.

Ben Vernon, 32, was more seriously injured and had several stab wounds to his torso and punctured a lung, officials said.

Alex Walbertt, 37, also had multiple wounds to his torso but was expected to be released from the hospital sometime Thursday night.

Ryan Allen Jones, 34, is suspected of stabbing the two men. He was being held in county jail without bail and faces charges of attempted murder, assault with a deadly weapon and resisting arrest.

"I've been around for 35 years and while we've had altercations," Fire Chief Javier Mainar said at a news conference, "I've never seen one that resulted in two firefighters facing a near-death experience."

Police were trying to determine a motive. Chief Shelley Zimmerman told reporters Thursday that Jones began crowding the firefighters and telling them what to do as they tried to render aid. Zimmerman said that Jones did not appear to be acquainted with the patient. 

“He was asked several times by the firefighters to move back,” she said. "He continued to interfere with the firefighters rendering the aid, and an altercation occurred."

The Associated Press contributed to this report.

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