LOS ANGELES — The driver parked outside a hotel and surveyed the leisurely summer scene at the Venice Beach boardwalk: Hundreds of people were sitting at cafes, walking along the seashore, or shopping at vendors selling jewelry or art.
Then, according to surveillance video, the man got into a large black car, steered around a vehicle barrier and accelerated mercilessly through the crowd, hitting one person after another as bystanders tried desperately to get out of the way.
Saturday’s hit-and-run killed an Italian woman on her honeymoon and injured 11 others who had been enjoying an afternoon near the beach at the height of vacation season.
A couple of hours later, authorities arrested a man on suspicion of murder after he walked into a police station in neighboring Santa Monica and said he was involved.
Nathan Louis Campbell, 38, of Los Angeles, remained jailed Sunday in lieu of $1 million bail.
Police declined to discuss a motive but Deputy Chief Kirk Albanese said there was no indication that the attack was a terrorist act or that anyone else was involved.
By the time it was over, the driver had covered about a quarter of a mile along the boardwalk before fleeing.
Witnesses reported a horrifying aftermath. Louisa Hodge described ‘‘blocks and blocks of people just strewn across the sidewalk,’’ with many bloodied and disoriented.
The Italian woman was identified as Alice Gruppioni, 32. Her family in Bologna told the Italian news agency LaPresse that she had been on her honeymoon after a July 20 wedding.
Gruppioni worked as a manager for the family business Sira group, which makes radiators. Her father, Valerio Gruppioni, runs the company and was formerly president of the Bologna soccer team, according to LaPresse. Her family declined to comment Sunday.
Another person was critically injured. Two others were taken to hospitals in serious condition. Eight suffered less serious injuries, police said.
According to security video and witness accounts, the driver parked next to the Cadillac Hotel and twice walked out to the boardwalk before getting into the Dodge Avenger.
He carefully maneuvered between a storefront and metal poles that had been erected to prevent anyone from driving onto the boardwalk.
Then he stepped on the accelerator and plunged into the crowd.
‘‘I heard a big ‘boom, boom,’ like the sound of someone going up and down the curb, it was super loud,’’ said Alex Hagan, who was working the desk at the hotel.
The driver knocked over two mannequins and an ATM and started hitting people, swerving from side to side and often running straight into victims. Video showed the car struck at least three vendors — a fortune teller, a couple selling jewelry, and a tattoo artist.
Two women who appeared to be in their 60s were also hit. Many people ran after the car, screaming and cursing as it sped away, Hagan said.
Golestan Alipour was bartending at Candle Cafe & Grill when the menacing vehicle drew near.
‘‘The restaurant was full. Everybody ran,’’ Alipour said.
It was not immediately clear how fast the car was going.
The driver eventually turned up a side street and headed away from the ocean. The car was later found abandoned less than 2 miles away, police said.
At the scene, detectives searched for evidence across the boardwalk, which is in a part of Los Angeles known for eccentricities. The 1.5-mile ribbon of asphalt — which runs along the sand a few hundred yards from the ocean — is home to galleries, restaurants, tattoo shops, skateboard parks, and the famous outdoor weight room known as Muscle Beach. The boardwalk can draw as many as 150,000 people on summer weekends.
Hodge said she and her friend, Ashley Taylor, had noted the large number of people walking along the seaside.
‘‘It was a really nice day. There were tons of people out. In fact, we were talking about how packed it was, because we were having a hard time getting through all the people,’’ Hodge said.
The two women stopped to buy ice cream and a couple of hats, which may have saved their lives. They stepped out of a store as emergency crews arrived.
Hodge saw a man and woman lying next to each other, wearing head braces, barely able to move but grasping hands.
Los Angeles Councilman Mike Bonin said there have been previous problems with motorists accidentally driving onto the boardwalk, especially during the evening, because many entrances aren’t blocked and there are no signs warning them about entering a pedestrian area.
However, four yellow metal poles blocked the roadway used by the hit-and-run driver, who squeezed past the barrier by driving onto a sidewalk, authorities said.
‘‘The frightening part,’’ Bonin said, was that this part of the boardwalk was ‘‘one of the more protected streets.’’
The crash was not far from where an elderly driver sped through an open-air farmer’s market in Santa Monica in 2003, killing 10 people and injuring more than 70 others.