FBI divers wrapped up a three-day search of a California lake where authorities suspect a couple inspired by Islamic State may have dumped evidence linked to their massacre of 14 people, an official said on Sunday, adding the team retrieved some objects.

The search at the lake in a public park 2.5 miles (4 km) north of the site of the Dec. 2 shooting at a regional center in San Bernardino, began on Thursday after reports the suspects were spotted nearby either before or after the attack.

ABC News and other news organizations had reported that the divers at San Bernardino Lake were looking for a computer hard drive that belonged to the married couple, Syed Rizwan Farook, 28, and Tashfeen Malik, 29.

But FBI spokeswoman Laura Eimiller declined on Sunday to describe the objects or say whether they appeared to be connected to the mass shooting.

"We have not commented on the items, or whether they are case-related, due to the ongoing investigation," Eimiller said, responding to a media report the objects retrieved in the search were not tied to the crimes under investigation.

"Divers tend to find all sorts of items in public lakes," she said, and any objects found "will be analyzed for evidentiary value in this case."

US officials have said their investigation has yet to turn up evidence that foreign militants directed Farook or Malik when they stormed a holiday gathering of Farook's co-workers and opened fire with assault rifles.

The couple fatally shot 14 people and wounded more than 20 in a rampage the FBI said it was treating as an act of terrorism inspired by Islamist militants. If that is confirmed, it would be the most lethal such attack on US soil since the Sept. 11, 2001, hijacked plane attacks on the World Trade Center and Pentagon.

Farook, the US-born son of Pakistani immigrants, and Malik, a Pakistani native he married last year in Saudi Arabia, were killed in a shootout with police hours after the assault in San Bernardino, 60 miles (100 km) east of Los Angeles.

The FBI has said the couple declared they were acting on behalf of Islamic State. But FBI Director James Comey has said there was no evidence the militant group was aware of them before the attack.

BACKLASH?

As authorities investigate the shooting, concerns have mounted about a possible backlash against Muslim-Americans after reports of vandalism at three Southern California mosques since Friday.

The incidents recalled threats and violence against Muslim targets in United States following the Sept. 11, attacks.

On Friday, a fire that appeared to have been intentionally set burned the entrance to a mosque in Southern California's Coachella Valley, 75 miles (120 km) from San Bernardino.

A 23-year-old man was arrested on suspicion of arson and committing a hate crime, according to the Riverside County Sheriff's Department.

On Sunday, police in the city of Hawthorne, 130 miles (210 km) west of Coachella Valley in Los Angeles County, were investigating separate acts of vandalism at mosques, apparently overnight, that authorities have classified as hate crimes.

The word "Jesus" had been spray-painted on a fence at an Ahmadiyya Muslim Community mosque and a plastic replica of a hand grenade was left in the parking lot, Hawthorne police said.

An official with the group said it was cooperating with police and the FBI and inviting members of the community to visit the mosque.

In another incident, "Jesus is the way" had been spray-painted on the front of the Islamic Center of Hawthorne, police said. – Reuters