SAN BERNARDINO, Calif. >> Federal authorities on Tuesday asked for the public’s help in filling out a gap in the whereabouts of the two assailants after they killed 14 people in last month’s attack in San Bernardino.

David Bowdich, the assistant director in charge of the FBI’s Los Angeles office, reiterated that there’s no evidence that the attack was foreign-directed, but said nothing has been ruled out.

He also said investigators have found no evidence there were any targets other than the Inland Regional Center, where Syed Rizwan Farook, 28, and his wife, Tashfeen Malik, 29, opened fire Dec. 2 on a holiday luncheon gathering of Farook’s co-workers in the county health agency.

Investigators specifically need information about an 18-minute gap in the timeline between the deadly attack at the center and the pursuit and shootout in which both attackers were killed.

Bowdich said investigators want to leave no stone unturned and hope to find out if the assailants contacted anyone or stopped anywhere between 12:59 p.m. and 1:17 p.m. that day. The rest of their movements through the adjacent cities of San Bernardino and Redlands in a rented black Ford Expedition have been tracked, he said.

“It’s possible that they stopped, whether it be a storage area, a residence, a business. It’s possible there was a contact made. We just don’t know,” Bowdich told reporters. “”It very well may not be an important fact, but until we close that gap we just don’t know for sure.”

He urged people to call if they have any information, including video.

After the shooting rampage, the couple visited an area lake at 11:45 a.m. and then appeared to zig-zag throughout the area, stopping at certain places, he said.

“There’s no rhyme or reason that we can make for it yet, however, again, that 18 minutes is critical, “Bowdich said.

Bowdich said authorities have carried out 29 search warrants, conducted 550 interviews and scoured social media to piece together a timeline of the couple’s whereabouts after the attack.

The request for assistance comes a day before a friend of Farook’s accused of providing the guns used in the massacre is scheduled to be arraigned in a federal court in nearby Riverside.

A grand jury last month indicted Enrique Marquez, who was Farook’s former next door neighbor, on charges that include making false statements when he bought the weapons and conspiring in a pair of previous planned attacks that were never carried out.