One key question, said the official, “is if they had any weapons or terror training in Pakistan.” The source described “some kind” of contact between Farook and people from the Nusra Front and the radical Shabab group in Somalia. It’s unclear what type of contact or with whom.

Authorities in Pakistan also said Friday that they were investigating whether Malik had ties to Islamic militant organizations.

Officials cautioned that Malik’s Facebook posting did not mean that the militant group directed her and her husband to carry out the Wednesday attack, and that investigators think it instead suggests that the couple had become self-radicalized.

A Facebook spokesman confirmed that the company had taken down the profile page that included the post cited by law enforcement officials. He said the post was discovered a day after the shooting when Facebook employees conducted a search of the site for the shooters’ names.