The latest on the mass shooting at a social services facility in San Bernardino, California (all times local):
A U.S. official says the FBI was treating the mass shooting in California as a potential act of terror but had reached no conclusion it was.
The official was briefed on the investigation but wasn't authorized to discuss it by name and spoke on condition of anonymity.
The official said Syed Rizwan Farook communicated with individuals who were under FBI scrutiny in connection with a terrorism investigation. But the official said the contact was with "people who weren't significant players on our radar," dated back some time, and there was no immediate indication of any "surge" in communication ahead of the shooting.
The official said Farook and his wife weren't on the FBI's radar before the shooting, which killed 14.
The official said the communication was a "potential factor" but cautioned that "contact with individuals who are subjects of investigations in and of itself doesn't mean that you are a terrorist."
- From Associated Press writer Eric Tucker in Washington, D.C.
One of the shooters who killed 14 people at a California social service center was a conditional resident in the U.S. after marrying a citizen.
The FBI says Tashfeen Malik came to the U.S. in July 2014 on a Pakistani passport and a so-called fiancée visa. To get the visa, she had to submit to an in-person interview and biometric and background checks to ensure she wasn't a threat to public safety or national security.
By law, Malik had 90 days to get married or leave the country. She became a conditional resident after marrying Syed Farook. Two years after the wedding, she could have applied to stay in the U.S. permanently.
Malik and Farook opened fire on a holiday banquet of Farook's co-workers and then died in a shootout with police Wednesday.
A U.S. intelligence official says one of the shooters who killed 14 people in California had been in touch on social media with extremists who are under FBI scrutiny.
The official would not further describe the contacts by Syed Rizwan Farook. He would not be quoted because he was not authorized to discuss the matter publicly.
The official says investigators are still trying to determine whether and how he became radicalized and whether he was in contact with any foreign terrorist organization.
- From Associated Press writer Ken Dilanian in Washington, D.C.
Rep. Adam Schiff, the top Democrat on the House Intelligence Community, says it's premature to conclude that one of the California attackers was self-radicalized or "moved by some international actor."
Schiff told CNN on Thursday that he had been briefed by the FBI in the morning and that information is continuing to come in.
He says it's possible that the killings of 14 people were connected to terrorism but that it's also possible it was workplace violence or a combination of the two.
He says investigators are looking through social media and chasing down both foreign and domestic leads to look for connections to terrorism.
But he says federal authorities are not in a position to conclude that Syed Farook self-radicalized.
A friend says a man who was killed in the rampage at a Southern California social service center worked with one of the shooters and they had a heated conversation about Islam two weeks before the attack.
It's not clear if the discussion was a factor in the attack.
Kuuleme Stephens says she happened to call 52-year-old Nicholas Thalasinos while he was at work and having a discussion with Syed Farook.
Thalasinos identified Farook by name and told her Farook believed Islam was a peaceful religion.
She added that Farook said Americans don't understand Islam.
Stephens says both men worked as county restaurant inspectors and regularly discussed politics and religion. Thalasinos identified as a Messianic Jew and was passionate about pro-Israel causes.
Thalasinos' wife, Jennifer Thalasinos, told The New York Times that her husband had talked about Farook but never said anything negative.
The military-style rifles used in the California shootings were legally purchased.
The FBI says authorities recovered two military-style rifles, two handguns and thousands of rounds of ammunition after the siege at a disability services center and a later shootout with police.
The two rifles were not specifically listed among models outlawed under California's tough gun laws. As long as both weapons included a cosmetic change affecting how bullets are loaded, they would have been legal in California.
The FBI says the suspected gunman, Syed Rizwan Farook, legally bought the handguns but someone else bought the rifles. The Bureau of Alcohol, Tobacco, Firearms and Explosives earlier said all four guns were legally bought.
Farook and his wife were killed in a shootout with police.
Authorities say the woman who helped her husband kill 14 people a banquet at a social service center in Southern California had a Pakistani passport and came to the U.S. on a fiancee visa.
David Bowdich, assistant director of the FBI's Los Angeles office, says Syed Farook, a U.S. citizen, traveled internationally and entered the U.S. with Tashfeen Malik in July 2014.
He said at a news conference Thursday that the bureau doesn't know all the countries Farook went to and that a motive for the shooting is not yet known.
San Bernardino Police Chief Jarrod Burguan says the couple had more than 1,600 bullets with them when they were killed in a gunbattle with police.
Police say the attackers who killed 14 people at a banquet in Southern California had more than 1,600 bullets with them when they were gunned down in their SUV.
San Bernardino Police Chief Jarrod Burguan said at a news conference Thursday that the shooters had more than 3,000 rounds of ammunition at their home, 12 pipe bombs and hundreds of tools that could be used to make improvised explosive devices.
Burguan says Syed Farook and his wife sprayed the room at a social service center in San Bernardino with bullets but police didn't know if any one person was targeted.
Police and the FBI say the attack was planned but they do not know a motive.
Police say they found 12 pipe bomb devices at a California home being searched in connection with a mass shooting as well as hundreds of tools that could be used to make improvised explosive devices.
San Bernardino Police Chief Jarrod Burguan said at a news conference Thursday that the attackers also left a device at the social service center where they opened fire. The device consisted of 3 connected pipe bombs with a remote control that apparently did not work.
Authorities say Syed Farook and his wife or fiancee killed 14 people at the center Wednesday. The chief says the attackers fired between 65 and 75 rounds at the center. They later died in a gunbattle with police.
Burguan also says the number of people wounded in the mass shooting in Southern California has risen from 17 to 21.
Investigators found 12 pipe bombs at home searched after killings in California, along with thousands of rounds of ammunition. During a press conference, police said all four guns used in the shooting were legally purchased.
President Barack Obama is ordering U.S. flags to be flown at half-staff to honor the victims of the shooting in California that left 14 people dead.
The White House says Obama signed the proclamation Thursday. It calls for flags to remain at half-staff through Monday and affects flags at the White House, public buildings, military installations, U.S. Navy ships, embassies and diplomatic missions.
Obama says it's possible the massacre was related to terrorism but that authorities still don't know. He says it's possible it was workplace-related or that there were mixed motives.
Authorities say Syed Farook and his wife or fiancee killed 14 people at a social service center Wednesday before dying in a gunbattle with police. He fired on colleagues at a holiday gathering for county health employees.
Divorce papers from the parents of one of the San Bernardino, California, attackers reveal an acrimonious split in which the wife accused her husband of being an abusive alcoholic.
The records obtained Thursday by The Associated Press show that Syed Farook's mother, Rafia, described her husband in 2006 as "irresponsible, negligent and an alcoholic."
She said she was forced to move out of her home with three of her children because her husband continually harassed her "verbally and physically and refused to leave the home."
She filed a no-contact, stay-away domestic violence protection petition on July 3, 2006. She alleged that same year that her husband attacked her while her kids were present, dropped a TV on her and pushed her toward a car.
Authorities say Syed Farook and his wife or fiancee killed 14 people at a social service center Wednesday before dying in a gunbattle with police.
President Barack Obama says it's possible the mass shooting in California was related to terrorism but that authorities still don't know. He says it's possible it was workplace-related or that there were mixed motives.
Obama is speaking in the Oval Office. He's assuring Americans that authorities will get to the bottom of what happened. The president also is calling for people to wait for facts before making judgments.
Obama says many Americans feel there's nothing they can do about mass violence. But he says "we all have a part to play."
The president says the nation must make it harder to carry out violence but acknowledged that the threat can't be eliminated completely. He says it will be important for all Americans, including state legislatures, to see what they can do.
Ten shooting victims are being treated at two hospitals following the massacre in San Bernardino, California.
San Bernardino County spokeswoman Felisa Cardona says all five patients at Arrowhead Regional Medical Center are in stable condition Thursday morning. She says one other patient left the hospital after being treated Wednesday.
Loma Linda University Medical Center is treating five patients for gunshot wounds. CEO Kerry Heinrich says two are in critical condition and three are in fair condition.
Heinrich praised first responders and hospital staff, saying "there's nothing really you can do to prepare for an event like yesterday."
Authorities say Syed Rizwan Farook and his wife or fiancee, Tashfeen Malik, killed 14 people in a precision attack Wednesday at a social service center before they died in a gunbattle with police.
U.S. Attorney General Loretta Lynch says the Justice Department will be offering "any and all assistance necessary" as the investigation into the California mass shooting continues.
Lynch is speaking at an event about criminal justice at the White House. She says the shooting in California was "unspeakable."
Lynch says the government doesn't know a lot yet about the incident. But she says the FBI, the U.S. Marshals Service and other federal authorities have been dispatched.
The attorney general says whatever the results of the investigation, there's no place for this type of violence in the U.S. She says that's not what the country stands for or works for.
Police and federal agents are for a second day searching a home in connection to the massacre in San Bernardino, California.
A search team combed the residence early Thursday in neighboring Redlands, about 7 miles from the shooting at Inland Regional Center.
A black sedan parked outside was also searched.
The home is where officers initially saw a vehicle matching the description of the suspects' SUV in the hours before the final gun battle that killed them. A bomb squad on Wednesday swept the building with robots.
Police didn't immediately say if the suspects - Syed Rizwan Farook and Tashfeen Malik - lived at the home. Public records show it is a possible residence of a family member of Farook.
Residents tell KABC-TV Redlands is a "sleepy little town" and expressed shock that the killers might be their neighbors.
Federal authorities say that the two assault rifles and two handguns used in the San Bernardino massacre were all purchased legally in the United States - two of them by someone who's now under investigation.
Meredith Davis of the Bureau of Alcohol, Tobacco, Firearms & Explosives says investigators are now working to make a connection to the last legal purchaser.
She says all four guns were bought four years ago but she's not saying whether they were purchased out of state or how and when they got into the hands of the two shooters.
Davis says California requires paperwork when guns change hands privately but many other states don't.
She also says the rifles involved were .223-caliber - powerful enough to pierce the standard protective vest worn by police officers, and some types of ammo can even plow through walls.
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