SAN BERNARDINO, Calif., Jan. 5 (UPI) -- Federal agents investigating the married couple accused of killing 14 people in a terror attack in Southern California last month are trying to figure out what the suspects did for a period of nearly 20 minutes after the assault that authorities cannot account for.
The Federal Bureau of Investigation is now focusing its investigation on that segment of the timeline, which agents have not been able to piece together. The time period in question lasts for 18 minutes after the mass shooting at San Bernardino's Inland Regional Center ended, Los Angeles FBI field office assistant director David Bowdich said Tuesday.
Investigators aren't yet certain what movements Syed Rizwan Farook and his wife, Tashfeen Malik, made between 12:59 p.m. and 1:17 p.m. local time on Dec. 2 -- a time span that occurred two hours after the deadly attack began.
Specifically, agents want to know whether they visited any businesses, dropped anything off or spoke to any individuals, the Los Angeles Times reported Tuesday.
Authorities are aware of a few locations the couple drove to after the shootings but don't know what they were doing there.
"A lot of zig-zagging around, going back and forth on the highway," Bowdich said. "There is no rhyme or reason to it that we can find yet."
Agents say what they do know is that Farook and Malik began shooting at the social services facility at 10:59 a.m. About four minutes later, the FBI said, the shooting stopped and the couple fled. Later, at about 3 p.m., police efforts to track down the suspects resulted in a high speed chase and shootout, during which Farook and Malik were quickly killed.
In addressing the timeline, Bowdich encouraged the public to come forward with any information -- particularly photographic evidence -- that can help investigators fill-in the gap.
The FBI timeline of the event begins at 8:37 a.m. when Farook left his home for the Inland Regional Center, where he worked and where a holiday party was being held that morning. Officials said he arrived ten minutes later, but left the center at 10:37 a.m. while the party was still going. He returned 20 minutes later, with Malik, to begin the assault.
So far investigators have said Farook, a 28-year-old Illinois-born citizen, and Malik, a 29-year-old Pakistani-born permanent U.S. resident, were motivated to launch the attack by radical Islamic activities overseas and had become self-radicalized in the years leading up to the mass shooting.
No evidence, however, has yet surfaced to indicate any established terrorist faction instructed or pressed the couple to plan or launch the attack.
Enrique Marquez, an acquaintance of Farook's, has since been charged with aiding terrorism for purchasing the two AR-15 assault rifles that were used in the attack. Officials said Marquez, 24, had discussed multiple potential terror plots with Farook in 2011 and 2012, though none were ever carried out.
With 14 victims killed, the San Bernardino attack is the deadliest terror attack in the United States since 9/11.