Tashfeen Malik, who alongside her husband, Syed Rizwan Farook, carried out a massacre in San Bernardino, California earlier this month, reportedly passed three American background checks as she moved to the United States from Pakistan. None of these background checks uncovered her social media posts supporting violent jihad.

The New York Times reported that American law enforcement officials recently found old and previously unreported social media posts made by Malik, who said on the Internet that she supported violent jihad and that she wanted to be a part of it. Immigration authorities said that they don't often review social media as part of their background checks, and there is a debate in the Department of Homeland Security, or DHS, over whether the act is appropriate.

Prior to her U.S. entry, Malik was vetted in three extensive national security and criminal background screenings, beginning with DHS officials checking her name against American law enforcement and national security databases, the New York Times wrote. Afterwards, her visa application was sent to the U.S. Department of State, which reviewed her fingerprints against other databases.

Finally, she headed to the U.S. in July 2014 and formally married Farook, then applied for her green card and went through another batch of criminal and security checks, which included two in-person interviews with a consular officer in Pakistan and with a U.S. immigration official, the news outlet noted.

Fox News wrote that Farook is a U.S. citizen whose family originated from Pakistan.

All these background checks came clear, with the Federal Bureau of Investigation, or FBI, saying that it didn't recover any incriminating information against Malik, while the DHS and State Department said they followed all policies and procedures, the New York Times reported.

President Barack Obama has cautioned against "a betrayal" of the U.S.' values when it comes to responding to threats, but he had ordered a review of the K-1 visa programs, which permits foreigners such as Malik to live in the U.S. to marry Americans for permanent residency and eventual citizenship, the New York Times noted. However, White House Spokesman Josh Earnest admitted on Thursday that the program deserves a second look now that an act of terrorism was carried out on American soil

Obama's administration is determining whether those background checks can be expanded without giving major delays to the program, the news outlet added. In an effort to guarantee that they did not miss threats from individuals entering the U.S., immigration officers are reviewing all of around 90,000 K-1 visas issued in the past two years. They are also considering issuing a moratorium on new ones while deciding whether changes should be formulated.