BERKELEY (CBS SF) — A Berkeley man has been charged with attempted murder and assault with a deadly weapon for allegedly stabbing a woman on an AC Transit bus on Monday night, authorities said Wednesday.

Berkeley police said in a statement that 24-year-old Eric Palmer was riding a bus on San Pablo Avenue near Chaucer Street shortly before 9:50 p.m. on Monday when “for no apparent reason” he walked down the aisle, pulled out a knife, said “watch this” and suddenly stabbed a 21-year-old woman who was seated nearby.

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Police said a 25-year-old man who witnessed the attack immediately took action by striking Palmer continuously with his skateboard, distracting Palmer from his attack.

However, police said Palmer was “so determined” to keep attacking the woman that he continued his alleged assault even after the Good Samaritan intervened.

Palmer eventually fled from the bus when it pulled over on San Pablo Avenue near Chaucer Street but he was soon detained by an officer who was flagged down by bus passengers, according to police.

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The woman suffered serious but non-life-threatening injuries and was transported to a local hospital to be treated, police said.

There was no apparent motive for the attack and the investigation into the incident is continuing, police said.

Authorities praised the actions of the passenger with the skateboard, saying that he intervened without hesitation and possibly saved the woman’s life.

Palmer, who is being held at the Berkeley Jail without bail, is scheduled to be arraigned at the Wiley Manuel Courthouse in Oakland at 2 p.m. on Thursday.

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