(Reuters) – Islamic State said on Saturday that a married couple who killed 14 people in California in an attack the FBI is investigating as an “act of terrorism” were followers of the militant group based in Syria and Iraq.
The group’s declaration, in an online radio broadcast comes three days after U.S.-born Syed Rizwan Farook, 28, and his spouse, Tashfeen Malik, 29, a native of Pakistan, carried out the attack on a holiday party for civil servants in San Bernardino, about 60 miles (100 km) east of Los Angeles.
The two died hours later in a shootout with police.
U.S. government sources have said Malik and her husband may have been inspired by Islamic State, but there was no evidence the attack was directed by the militant group or that the organisation even knew who they were. The party the couple attacked was for workers in the same local government agency that employed Farook.
If Wednesday’s mass shooting proves to have been the work of people inspired by Islamist militants, as investigators now suspect, it would mark the deadliest such attack in the United States since Sept. 11, 2001.
“Two followers of Islamic State attacked several days ago a centre in San Bernadino in California,” the group’s daily online radio broadcast al-Bayan said on Saturday.
The broadcast came a day after Facebook confirmed that comments praising Islamic State were posted around the time of the mass shooting to an account on the social media website established by Malik under an alias.
However, it was uncertain whether the comments were posted by Malik herself or someone with access to her page.
“I know it was in a general timeline where that post was made, and yes, there was a pledge of allegiance,” David Bowdich, assistant director of the Federal Bureau of Investigation’s Los Angeles office, told a news conference about a reported loyalty pledge posted on Facebook by Malik on the day of the attack.
A Facebook Inc spokesman said the profile in question was removed by the company on Thursday for violating its community standards barring promotion or praise for “acts of terror.” He declined to elaborate on the material.
CNN and other news media outlets reported the Facebook posts on Malik’s page included a pledge of allegiance to Islamic State leader Abu Bakr al-Baghdadi.
FBI officials said mounting signs of advanced preparations, the large cache of armaments amassed by the couple and evidence that they “attempted to destroy their digital fingerprints” helped tip the balance of the investigation.
“Based on the information and the facts as we know them, we are now investigating these horrific acts as an act of terrorism,” Bowdich told reporters.
He said the FBI hoped examination of data retrieved from two smashed cellphones and other electronic devices seized in the investigation would lead to a motive for the attack.
The couple had two assault-style rifles, two semi-automatic handguns, 6,100 rounds of ammunition and 12 pipe bombs in their home or with them when they were killed, officials said. And Bowdich said they may have been planning an additional attack.