During a news briefing last week, Bowdich said Farook brought a bag containing the pipe bomb into the facility when he arrived at 8:37 a.m. An FBI affidavit said the device was made of three galvanized steel pipes and smokeless powder and was attached to a remote-control toy car. The bomb was “armed and ready to detonate.”

Agents found a remote control for a toy car in the couple’s SUV, the affidavit said.

But this marks the first time officials have said they believe the couple attempted to detonate the device.

Farook and Malik drove around San Bernardino and Redlands between the time of the attack and their deaths in a gun battle with police hours later. In that three-hour, 42-minute window, the couple did not stray far from the facility, according to Bowdich. At one point, they even returned to Waterman Avenue and drove in the direction of the building.

A federal law enforcement source previously told The Times that it is possible the couple were unable to detonate the device because the remote was out of range. Sprinklers that went off after the shooting could have also interfered with the explosives, said the source, who requested anonymity to speak candidly about an active investigation.