Sen. Ted Cruz blasted the Department of Homeland Security Friday, saying its "willful blindness" on mostly excluding social media from visa background checks appeared to have contributed to the San Bernardino, Calif., terror attack.Into Homeland Security Secretary Jeh Johnson, Deputy Secretary Alejandro Mayorkas and Leon Rodriguez, the director of U.S. Citizenship and Immigration Services, the Texas lawmaker and GOP presidential candidate called the policy "exceedingly dangerous" and "nothing short of colossal negligence.""In light of the terrorism in San Bernardino on December 2, it appears that DHS's policy of willful blindness toward the reality and danger of radical Islam in the United States contributed to the death of 14 Americans here at home," he wrote."Indeed, rather than being an aberration, this policy seems to be all too consistent with other policies of DHS and USCIS, which restrict fraud and terrorism investigators from fulfilling their missions and (arguably) enable fraudulent and dangerous people to enter and remain in the United States.”Cruz raged "much more information is needed" about the current policy."Given the rise and proliferation of social media, and younger generations’ increasing reliance on these media, DHS cannot afford to have policies that are blind to information made available on social media and the Internet," he wrote.The letter comes a day after several Republicansthe Obama administration's easing of new visa requirements for certain European travelers who have visited Iran, Iraq, Syria, or Sudan in the last five years.In his letter, Cruz noted Tashfeen Malik, who, along with her husband, Syed Rizwan Farook, murdered 14 Americans in the Dec. 2 attack in San Bernardino, had reportedly made comments on social media in support of radical Islam and anti-Western jihad prior to the attack."These same news accounts have providedabout whether social media content could be viewed by federal investigators who were responsible for conducting the background investigations of such foreign nationals," Cruz wrote.Cruz wants the department to preserve all internal documents or information on using social media for investigations. Cruz also wants to know if DHS believes it's illegal to access secret social media as part of its visa background check process.