SAN BERNARDINO, Calif. (AP) — The couple who carried out the San Bernardino massacre had been radicalized “for quite some time” and had taken target practice at area gun ranges, in one case within days of the attack that killed 14 people, the FBI said Monday.

In a chilling twist, authorities disclosed that a year before the rampage, Syed Farook’s co-workers at the county health department underwent “active-shooter” training in the very conference room where he and his wife opened fire on them last Wednesday.

It was not immediately clear whether Farook attended the autumn 2014 training session on how to react to a workplace gunman, county spokeswoman Felisa Cardona said. It was held for members of the department’s environmental health division, where Farook was a restaurant inspector.

On Monday, one employee who had been in the room when Farook and Tashfeen Malik launched their attack on a holiday luncheon said colleagues tried to do just as they had been trained — find protection and stay quiet.

“Unfortunately the room just didn’t provide a whole lot of protection,” said Corwin Porter, assistant county health director.

Farook, a 28-year-old born in the U.S. to a Pakistani family, and Malik, a 29-year-old immigrant from Pakistan, were killed in a gunbattle with police hours after the bloodbath.

“We have learned and believe that both subjects were radicalized and have been for quite some time,” said David Bowdich, chief of the FBI’s Los Angeles office.

He added: “The question we’re trying to get at is how did that happen and by whom and where did that happen? And I will tell you right now we don’t know those answers.”

He also said the Muslim couple had taken target practice at ranges in the Los Angeles metropolitan area, with one session held within days of the rampage.

In addition, authorities found 19 pipes in the couple’s home in Redlands, California, that could be turned into bombs, Bowdich said. The FBI previously said it had found 12 pipe bombs.

Newly released emergency radio transmissions from the fast-moving tragedy show that police identified Farook as a suspect almost immediately. Witnesses said he had left the luncheon about 20 minutes before the shooting began.

It was unclear how he was identified so quickly, given that witnesses said the attackers wore black ski masks. Bowdich would not address that question.

Twenty-one people were hurt, in addition to the 14 dead. At least six people remained hospitalized, two in critical condition.

President Barack Obama said in a prime-time address Sunday night that the attack was an “act of terrorism designed to kill innocent people.”

He said that the two killers had “gone down the dark path of radicalization” but that there was no evidence they were part of a larger conspiracy or were directed by an overseas terror organization.

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 weapons got into the couple’s hands.

Marquez has not been charged with a crime, and it is unclear if he did anything illegal.

Meanwhile, most of the county’s 20,000 employees went back to work for the first time since the rampage five days earlier engulfed the community in shock and mourning.

“To honor them, to express our gratitude for their unimaginable sacrifice, we have to fight to maintain that ordinary,” County Supervisor Janice Rutherford said of the victims. “We can’t be afraid of our lives, of our community, of our neighbors, of our co-workers.”

Authorities said that they have tightened security at county buildings and that counseling centers and a hotline have been set up for employees in distress.

Employees in the environmental health division, where many of the victims worked, will be off until next week.

In announcing the return to work, Trudy Raymundo, county health director, recalled that she was about to give a presentation when the killers opened fire.

“We held each other and we protected each other through this horrific event,” she said, “and we will continue to hold each other and protect each other.”

At the same news conference were some of the surgeons who rushed to treat the victims.

“What really bothers me most,” said Dr. Dev GnanaDev, chief of surgery at Arrowhead Regional Medical Center, “is that none of the 14 who perished had a chance.”

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Associated Press writers Rob Gillies in Toronto and Amy Taxin and Brian Skoloff in San Bernardino contributed to this report.

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This story has been corrected to show the full wording of Bowdich’s quote about the couple’s radicalization.