An M-80 explosive device went off at around the same time an SUV was vandalized in the area, said Los Angeles Police Deputy Chief Michael Downing. Investigators initially thought the vehicle was the source of the blast.
The bomb squad sent in robots, and officers throughout the area were placed on alert, but investigators now believe it likely was not a bomb that broke the window and created a small hole in the door of an SUV, Los Angeles Police Lt. John Romero said.
A caller reported hearing a blast at 7:30 a.m. in a commercial area of San Pedro. A short time later a patrol officer with the Port Police discovered the damaged Lincoln Navigator in the underground garage of the Clarion Inn.
Investigators found debris away from the SUV that helped them determine the blast was a firecracker, police said.
"On closer inspection and using their training, bomb squad is confident the damage was caused by something other than a bomb. Based on what we know now, they're scaling the operation way back," Romero said.
Downing said investigators ruled out any connection to terrorism. No arrests were made.
Romero said the LAPD has classified it as a vandalism case and detectives will be looking at surveillance tape of the garage and impounding the SUV to search it for clues.
The Navigator is owned by Kent Whitman of San Jose. He returned Sunday from a seven-day Mexican cruise and found that the hotel where he left his SUV was evacuated, then learned that the evacuation was because of damage to his vehicle.
"We got off our cruise ship and our car got vandalized. We don't know what exactly happened," Whitman told an Associated Press reporter at the scene. "We had a GPS system. That's the only thing that's gone."
Whitman said he got engaged on the cruise and Sunday is his birthday.
Rudy Pastrano, the owner of a diner about two blocks from the hotel, said he was preparing the day's menu when he heard a loud sound.
"I was cooking my food and I heard something like 'boom'! I said, 'What happened?' And I checked everything in the kitchen but saw nothing. An hour later I went outside and saw a lot of police," he said.
Streets were shut down and police briefly set up a command center south of the hotel. The roads were reopened around 11:15 a.m.
Police said there were no reports of injuries or damage to the hotel.
"We always take the potential for an explosive device very seriously," the LAPD said in a statement Sunday night. "This incident turned out to be the best-case scenario."
Associated Press Reporter Thomas Watkins and Christopher Weber contributed from Los Angeles.