WASHINGTON — The F.B.I. is now treating the San Bernardino shooting by a husband and wife that killed 14 and wounded 21 as an act of terrorism, an agency official said Friday.
“As of today, based on the information and facts as we know them,” the agency is investigating this “as an act of terrorism,” David Bowdich, the assistant F.B.I. director in charge of the Los Angeles office, said at a news conference. The agency will be taking over the investigation from local officials.
Mr. Bowdich did not offer any details about why the bureau had made the determination, saying only that “there’s a number of pieces of evidence that has pushed us off the cliff.”
The shift in the investigation game shortly after federal law enforcement officials said the woman who helped carry out the shooting in San Bernardino, Calif., Tashfeen Malik, had pledged allegiance to the Islamic State in a Facebook posting.
There is no evidence the Islamic State directed Ms. Milik , and her husband, Syed Rizwan Farook, to stage the attacks, the officials said. But the Facebook post has led investigators to believe that the couple took inspiration from the group, they said.
“At this point we believe they were more self-radicalized and inspired by the group than actually told to do the shooting,” one officials said, speaking on the condition of anonymity because the investigation is continuing.
Islamic terrorists have used the oath of allegiance, called a bayat, to declare their loyalty to specific groups and leaders. To become a member of Al Qaeda, for instance, terrorists historically swore their devotion to Osama bin Laden.
The posting, which had been removed from the social media site, provides one of the first significant clues to the role that Ms. Malik, 27, played in the attacks.
She was born in Pakistan, and traveled on a Pakistani passport, but grew up in Saudi Arabia, according to Dr. Mustafa H. Kuko, director of the Islamic Center of Riverside, which Mr. Farook attended for a few years.
“They were living in Saudi Arabia, but they were Pakistanis,” he said. “They had been in Saudi Arabia for a long time. She grew up in the city of Jeddah.”
Ms. Malik returned to Pakistan for college, graduating in 2012 from Bahauddin Zakariya University in Multan with a degree in pharmacy, according to local officials in the Layyah District of Punjab Province. They said that her family was originally from a town there, Karor Lal East, and that her father, Malik Gulzar Aulakh, moved with his family to Saudi Arabia about 20 years ago, later moving to the United States. Officials in Layyah said intelligence officials had visited on Friday and were looking for relatives of Ms. Malik.
Pakistani officials consider the area a center of support for extremist jihadist groups, including Lashkar-e-Taiba. Some of the most high-profile attacks against the Pakistani military in 2009 were led by a native of the same rural area: Umar Kundi, a medical doctor who became an operative for Al Qaeda. In addition, Multan, an ancient city in Punjab, is considered a hotbed of radicalism.
A Pakistani intelligence official, speaking on the condition of anonymity to discuss an continuing investigation, said security officials were looking into Ms. Malik’s time in Pakistan, as well as possible travel there by Mr. Farook.
In recent months, the F.B.I. has been particularly concerned that so-called homegrown extremists might be inspired by the Islamic State to stage attacks in the United States, law enforcement officials say. Even before the attacks in Paris last month, the agency had heavy surveillance on at least three dozen individuals who the authorities were concerned might commit violence in the group’s name.
The F.B.I. refocused its efforts on these individuals earlier this year in response to a shift in tactics by the Islamic State, law enforcement officials said. Instead of trying to persuade Americans to travel to Syria to join the Islamic State, the group began calling on its sympathizers and followers in the United States to commit acts of violence at home.
“We’ve especially focused on the portfolio of people we’re investigating for the potential of being homegrown violent extremists,” the F.B.I. director, James B. Comey, said last month at a news conference. “That is, people consuming the propaganda. So those investigations are designed to figure out where are they on the spectrum from consuming to acting.”
“Within that group we’re trying to focus on those we think might be at the highest risk of being a copycat,” Mr. Comey said, referring to those who may try to follow the attackers in Paris. “And so we are pressing additional resources, additional focus against those. That’s the dozens.”
On Friday morning, the landlord of the building where Mr. Farook and Ms. Malik lived in Redlands, Calif., allowed journalists into the cramped townhouse near San Bernardino, which investigators had spent nearly two days scouring, leading to the rare sight of dozens of reporters and photographers trampling through what, the day before, had been a crime scene they were not even allowed to approach. Plywood was nailed over the openings where the police and F.B.I. knocked out the doors and windows of the duplex townhouse, but the sheet of wood across the front entrance had been pried off to allow entry.
In an upstairs bedroom documents including driver’s licenses, credit cards and a Social Security card, all in the name of Mr. Farook’s mother, were strewn across a bed, while tabletops and other surfaces held more papers and books, including copies of the Quran. In the small living room, furniture shared space with a treadmill, a baby bouncer, rolled-up blankets and suitcases, and in the kitchen there was a sink full of dirty dishes and a refrigerator full of food, as if the occupants were expected back at any moment.
When asked whether there was a concern about the scene, and any evidence it contained, being secure, a spokeswoman for the F.B.I. office in Los Angeles said “our search is over,” and refused to comment further.
In the days leading up to the shooting, the couple took several steps to delete their electronic information, in an apparent effort to cover their tracks, officials said. The efforts — along with the 12 pipe bombs the couple had made — have led authorities to believe that the shooting was premeditated.
As investigators search for signs of a political or religious motivation for the massacre, the discovery of Ms. Malik’s Facebook posting has forced them to consider whether any radical impetus for it came from her more than from the husband, or from both. The couple were killed in a shootout with the police after the attack.
Mr. Farook, 28, was a United States citizen, born in Illinois, whose parents were from Pakistan. F.B.I. officials came up with no hits when they searched agency databases for his name, according to law enforcement officials. That is significant because it meant that not only was Mr. Farook never the focus of an investigation, he was also never mentioned by anyone else interviewed by the F.B.I., even in unrelated cases.
The bureau, however, has uncovered evidence that Mr. Farook had contact with five individuals on whom the F.B.I. had previously opened investigations for possible terrorist activities, law enforcement officials said. It was not clear, however, how significant the contacts were.
One individual contacted was associated with the Shabab, the Islamist militant group in Somalia. Another was associated with the Nusra Front, the Qaeda wing in Syria. None of the other three were tied to the Islamic State or core Al Qaeda. All five inquiries was closed, and the contacts were made a few years ago, not recently, the authorities said.
A cellphone Ms. Malik had with her on Wednesday had almost nothing on it — no social media apps or encrypted apps — leading investigators to suspect that it might have been a “burner phone,” meant to be used and discarded, the officials said.
Mr. Farook had posted profiles on Muslim dating websites, and apparently the couple met online. He told co-workers last year that he was traveling to Saudi Arabia to meet his bride, and both American and Saudi officials have confirmed that he spent more than a week in that country in July 2014.
Mr. Farook, was an American citizen, and he and Ms. Malik traveled to the United States together in July 2014, David Bowdich of the F.B.I. in Los Angeles said at a news conference. He said she had traveled with K-1 visa, a special visa that allows people to come to the country marry an American citizen. A couple has to marry within 90 days; after that the K-1 visa expires.
Mr. Farook applied for a permanent resident green card for Ms. Malik on Sept. 20, 2014, within the legal 90-day limit, a federal official said. She was granted a conditional green card in July 2015. As a routine matter, to obtain the green card the couple had to prove that their marriage was legitimate. Ms. Malik also had to pass criminal and national security background checks that used F.B.I. and Department of Homeland Security databases.