LOS ANGELES — Police have arrested a motorcyclist who set off a chain-reaction crash on a Southern California freeway that was caught on video last year and gained widespread attention online, authorities said Wednesday.

Andrew Flanigan, 45, was arrested on suspicion of assault with a deadly weapon, reckless driving and hit-and-run in connection with the June 2017 crash in Santa Clarita, California Highway Patrol Assistant Chief Mark Garrett said.

Witnesses said a sedan had cut off Flanigan’s motorcycle before he pulled up alongside the car and kicked the driver’s side door.

Video from another motorist showed the sedan veering into the motorcyclist before it crashed into the freeway’s center media and lost control, slamming into a pickup truck. The truck overturned, injuring the driver, before Flanigan drove off.

Investigators identified Flanigan as a suspect about a week after the crash but did not immediately arrest him as they built their case, Garrett said.

“We monitored this gentleman because we didn’t believe he was an ongoing public safety threat,” Garrett said at a news conference.

Investigators haven’t charged the driver of the sedan because they concluded that Flanigan was “most responsible” for the crash, authorities said.

A telephone number listed for Flanigan in public records was not in service Wednesday.

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