(ABC NEWS) — The FBI has officially decided to investigate the deadly San Bernardino shooting as an “act of terrorism” after they determined that there was “extensive planning” involved with the attack.
Bowdich noted that investigators had found two broken cell phones that they believe shows that the couple was actively trying to cover their tracks.
“We have retained those cell phones and we do continue to exploit the data from the cell phones,” Bowdich said. “We do hope that the digital fingerprints that were left by these two individuals will take us towards their motivation. That evidence is incredibly important.”
Family history and background of the married couple that turned into mass shooters is still at the center of the investigation.
Suspects Syed Farook and his wife, Tashfeen Malik, were killed by police in a shootout after their deadly attack, which they had apparently planned, officials said. In addition to having plenty of ammunition for another attack, sources told ABC News they also made sure to cover their tracks.
Police detailed the extent of the arsenal of a dozen pipe bomb-style devices and more than 4,500 rounds of ammunition that were found at the couple’s Redlands, California, home, as well as the 1,600 rounds they had in the rental car they were driving during their face-off with police.
Investigators were concerned when they went to search the couple’s home that there might have been explosives rigged to go off, because there was a pipe bomb at the scene of the shooting that had a remote detonator attached.
“We took our time in securing it, making sure we went in that house, secured it safely. That’s where we discovered the other pipe bombs,” San Bernardino police Chief Jarrod Burguan said Thursday.
Burguan noted that police did secure “some other evidence — computer evidence, cellphones,” but that does not mean that investigators will have instant access into the suspect’s digital trail.
Sources have told ABC News that mobile phones, hard drives and virtually anything with digital memory associated with Farook and Malik had been smashed when they were found by investigators.
FBI computer forensics analysts in Orange County, California ,and at the FBI lab in Quantico, Virginia, will try to reconstruct and extract any digital information they can, which sources said will be painstaking work.
One law enforcement source told ABC News that while investigators have some capabilities to mine information from damaged digital media, “they are not miracle workers.”
Another main focus of the investigation is to determine whether the deadly attack — which left 14 victims dead and 21 others injured — legally qualifies as an act of terrorism.
The terrorism classification will be determined once investigators are able to work out the motive of the attack, which remains unknown.
“We do know that the two individuals who were killed were equipped with weapons and appeared to have access to additional weaponry in their homes. But we don’t know why they did it,” President Obama said Thursday.
“It is possible that this was terrorist-related but we don’t know. And it’s also possible that this was workplace related.”
ABC News’ Pierre Thomas and Jack Date contributed to this report.