The Muslim husband and wife behind the mass shooting in San Bernardino began erasing their digital footprint a day in advance of the deadly attack, deleting email accounts, disposing of hard drives and smashing their cellphones, according to law enforcement investigators who are treating the probe as a counterterrorism case.
Investigators edged closer Thursday to the conclusion that Syed Rizwan Farook and his wife, Tashfeen Malik, were radicalized by Islamist extremists either in the U.S. or during trips to the Middle East, including Saudi Arabia.
Intelligence sources said there is still no explicit evidence linking the two to known terrorists on U.S. or foreign watch lists and that the couple was not on the FBI’s radar before Wednesday’s deadly shooting rampage. But their cache of thousands of rounds of ammunition and explosives found in a home that the couple rented raises major concerns about a wider plot, or a plan to act on their own to hit other targets.
Authorities have tracked down at least four people from the Los Angeles area who were previously under investigation by U.S. counterterrorism officials and were found to have had communication with Farook in the past, said a law enforcement source involved in the investigation.
But details about the individuals were murky. The law enforcement source said the last contact any of the four had with Farook was in June, and asserted that nothing fruitful came from the interviews about Wednesday’s attack.