The man suspected of being behind the wheel of a car 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.

In a statement Monday, he called his wife "an immense gift: a gift that no one can ever understand. She gave happiness and joy to anyone who had the luck to know her.

"About our love, you cannot say more than it will remain a dream from which we will never wake," he said.

One person was critically injured and two others were taken to hospitals in serious condition. The 13 others all received less severe injuries.

Little is known about Campbell, who is being held on $1 million bail. No relatives or close friends have emerged since the incident to talk about him, and police have revealed scant details.

Campbell lived in Colorado as recently as last year. He was evicted from his apartment in Denver for not paying $655 in rent in March 2012, records show.

He was sentenced to five days in jail after pleading guilty to shoplifting at a Denver supermarket in February 2009. Five months later, he was accused of trespassing at an outdoor mall in Denver and sentenced to 10 days in jail, court records show.

California authorities said no one with his name and birth date had a state driver's license.

Police have not yet presented their case to prosecutors, and Campbell was not expected in court until at least Tuesday.

Police said Campbell initially parked outside a hotel and surveyed the boardwalk, where hundreds of people were sitting at cafes, walking along the seashore or shopping for jewelry, art or other items at vending stands.

Surveillance video showed a driver getting into a Dodge sedan, steering around a vehicle barrier and careening through the crowd.

Two mannequins and an ATM were knocked down as the car started hitting people. It swerved from side to side, often running straight into victims. The car struck at least three vendors _ a fortune teller, a couple selling jewelry and a woman tattoo artist.

Witnesses said the car was traveling at least 35 mph (56 kph) along the crowded boardwalk.

The car eventually turned up a side street and headed away from the ocean. The vehicle was abandoned less than two miles (three kilometers) away.

People were "stumbling around, blood dripping down their legs, looking confused not knowing what had happened, people screaming," said Louisa Hodge, who described "blocks and blocks of people just strewn across the sidewalk."

An autopsy by the Los Angeles County coroner concluded Gruppioni died from blunt-force trauma to the head and neck. Her death has been classified as a homicide.

Gruppioni was a general manager for the family business that makes radiators. Her father, Valerio Gruppioni, runs the company and was formerly president of the Bologna soccer team, according to the Italian news agency LaPresse.

Gruppioni's aunt said that hours before her niece was killed, she shared stories of her honeymoon travels by phone with her parents in Italy.

"She was beyond happiness," Katia Gruppioni said.

She demanded justice after the rampage.

"The only thing I want, that he is absolutely not set free. I don't want this person to be around," she told The Associated Press.

Gruppioni's family described her as a devoted businesswoman with a romantic side, who never stopped dreaming about her bridal gown and meeting Prince Charming.

"She was robbed of her life while living her dream visit to California with her husband and this was a tremendous injustice," the family said in a statement.

A makeshift boardwalk memorial for Gruppioni continued to grow Monday, with mourners placing a note in Italian expressing condolences and a painting that reads "Venice loves you, Alice."

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Associated Press writers P. Solomon Banda in Denver, Colleen Barry in Milan, and Raquel Maria Dillon contributed to this report.