The husband and wife who carried out the San Bernardino shootings had been radicalized and had taken part in target practice, once within days of the attack that killed 14 people, the FBI said Monday.
"We believe both were radicalized and had been for some time," said David Bowdich, assistant director of the FBI's Los Angeles office. But the said investigators are still trying to establish when, where and by whom they were influenced.
He also said Syed Farook, 28, and his wife, Tashfeen Malin, 29, had taken target practice at ranges within the Los Angeles metropolitan area, with one session held within days of last week's rampage.
In addition, authorities found 19 pipes in the couple's home that could be turned into bombs, Bowdich said.
The couple opened fire with assault rifles Wednesday on a holiday luncheon for Farook's colleagues. Husband and wife were killed hours later in a shootout with police.
In a chilling twist, authorities on Monday said that a year before the rampage, Farook's co-workers underwent "active-shooter" training in the very room where he and his wife opened fire. It was not immediately clear whether Farook attended the 2014 training session, county spokeswoman Felisa Cardona said.
"Unfortunately, the room just didn't provide a whole lot of protection," said Corwin Porter, assistant county health director.
The two assault rifles used in the attack had been legally purchased by an old friend of Farook's, Enrique Marquez, authorities said, but they are still trying to determine how the couple got the weapons. Marquez has not been charged with a crime.
The FBI would not release details on where the couple practiced their shooting. But John Galletta, an instructor at Riverside Magnum Range, said Farook had been there and brought his own rifle. Galletta said he never spoke to Farook and that no one had seen his wife around there.
Farook's estranged father, also named Syed Farook, told the Italian newspaper La Stampa that his son shared the ideology of the Islamic State group and was fixated on Israel.
Malik attended a religious school in the Pakistani city of Multan briefly between 2013 and 2014 but didn't receive a diploma, Farhat Hashmi, founder of Al-Huda International Seminary, said in a statement on her website. The school is a women-only madrassa with locations across Pakistan and in the U.S. and Canada.
Hashmi has been criticized for promoting a conservative strain of Islam.