LOS ANGELES — The man suspected of being behind the wheel of a sedan that careened down the crowded Venice Beach boardwalk last weekend, killing an Italian newlywed on her honeymoon and injuring 16, is a transient who served brief stints in jail in Colorado, authorities said Monday.

Nathan Louis Campbell, 38, had been in the Los Angeles area a short time but had no fixed address, and police have been unable to find any evidence he was working.

Investigators believe Campbell, who was arrested for investigation of murder after he walked into a police station several hours after the rampage on Saturday, was driving his own car, Los Angeles police Cmdr. Andrew Smith said.

“I think we can safely say, when he turned himself in … he implicated himself in the Venice incident,” Smith said.

Investigators have yet to provide an explanation why the driver maneuvered around a vehicle barrier early that evening and plowed into tourists and vendors along the fabled walkway bordering the Pacific, killing Alice Gruppioni, 32.

Her new husband, Christian Casadei, was at her side. He suffered minor injuries.

Campbell is being held on $1 million bail.