The New York Times reported on Sunday that Ms. Malik had talked openly about jihad on social media before she applied for a visa to come to the United States. While those remarks were made online, Mr. Comey said, they were “direct private messages” and not easily accessed. Nevertheless, the F.B.I. was able to obtain them in the days since the attacks.
The suggestion that Malik had posted publicly about jihad was invoked during the Republican presidential debate Tuesday night, as Sen. Ted Cruz of Texas criticized the Department of Homeland Security and said officials had overlooked such a post.
“It’s not a lack of competence that is preventing the Obama administration from stopping these attacks,” Cruz said during the debate. “It is political correctness. We didn’t monitor the Facebook posting of the female San Bernardino terrorist because the Obama DHS thought it would be inappropriate. She made a public call to jihad, and they didn’t target it.”
Carly Fiorina, a business executive, said during the debate that “every parent in America is checking social media and every employer is as well, but our government can’t do it.”
Speaking at 1 Police Plaza, the New York Police Department’s headquarters in Lower Manhattan, Comey said the FBI follows the law when investigating people.
“We don’t intercept the communications of Americans…without predication, without probable cause or belief that they are involved in terrorism or serious criminal activity,” he said. “If we don’t know anything about somebody we are not combing through their emails or direct messages.”
Comey came to New York to commemorate the Joint Terrorism Task Force, which was founded in 1980 and the first of its kind in the country. Today there are more than 100 task forces around the United States dedicated to fighting terrorism. He also addressed a large audience of local law enforcement officials and private sector representatives.
Afterward at a gaggle with reporters, Comey reiterated that Malik and Farook didn’t appear to be directed by a foreign terrorist organization.
So far, Comey said, the FBI hadn’t turned up any indications that Farook had connections to any of the four California men charged in 2012 with plotting to travel overseas and kill Americans. Investigators believe that Farook might have been taking steps in 2012 to mount an attack against a high school or college but got spooked after the men were arrested.
According to court testimony, Arian Ahmad Badal, of Pomona, Calif., was driving three of the men when the FBI arrested them in November 2012.
Badal, who’s studying to be an imam and was never charged in that plot, said in an interview at his home that he never met Farook or his wife.
“I did not know him and never heard of him until now,” he said. Badal said the FBI had not interviewed him.
The Department of Homeland Security issued a bulletin Wednesday noting that officials are “especially concerned that terrorist-inspired individuals and homegrown violent extremists may be encouraged or inspired to target public events or places.”
DHS officials had previously said they would add a new level to their terrorism advisory system amid growing anxiety after the recent attacks in San Bernardino and Paris. In the bulletin released Wednesday, the department also warned Americans to expect stronger security at public places and events as well as an increased law enforcement presence.
Berman reported from Washington. Sari Horwitz contributed to this report from San Bernardino, Cal.
[This story has been updated.]