Family members of three victims claim that the companies permitted the Islamic State militant group (ISIS) to flourish on social media.
Police Foundation document also details the carnage found at the scene of the shooting, which killed 14 people.
"Terrorists must not be permitted to provide for their designated beneficiaries through their crimes," says U.S. Attorney Eileen Decker.
A Gallup poll found that 67 percent of Americans believed more attacks were "very likely" or "somewhat likely."
Homegrown extremists such as the San Bernardino attackers give ISIS a terrifying new weapon.
Syed Farook and Tashfeen Malik were influenced by foreign militant organizations, FBI Director James Comey said.
Authorities say Syed Farook and Tashfeen Malik killed 14 people in California last week.
Pakistani officials said Malik was from Karor Lal Esan, a city in southern Punjab province.