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

Laura Eimiller, a FBI spokeswoman, declined to describe the objects or say whether they appeared to be connected to the mass shooting earlier this month.

“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 that the objects were not tied 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.”

Since Thursday, divers have been searching the San Bernardino lake, in a public park, about 2.5 miles north of the site of the shooting.

U.S. officials have said their investigation has yet to turn up evidence that foreign militants directed Syed Rizwan Farook, 28, or Tashfeen Malik, 29, when the married couple stormed a holiday gathering of Farook’s co-workers on Dec. 2 at a regional center in San Bernardino and opened fire with assault rifles.

The couple shot dead 14 people and wounded more than 20 in a rampage the FBI said it was treating as an act of terrorism inspired by Islamic militants. If that is confirmed, it would be the most lethal such attack on U.S. soil since Sept. 11, 2001.

Farook, the U.S.-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 east of Los Angeles.

ABC News and other news organizations have reported that the FBI divers at the lake were looking for a computer hard drive that belonged to the couple, but Eimiller declined to confirm that on Saturday.

The underwater search stemmed from leads indicating that Farook and Malik had been in the vicinity of Seccombe Lake on the day of the killings, the FBI has said.

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 prior to their attack.

On Friday, a fire that appeared to have been intentionally set burned the entrance to a mosque in Southern California’s Coachella Valley, some 75 miles 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.

Muslim Americans have said they are worried about a backlash, as happened in the aftermath of the Sept. 11, 2001, attacks.