UPDATE: Dec. 3, 2015, 1:53 PM ET
San Bernardino, California authorities said two suspects who were heavily armed when they gunned down 14 people at a holiday party for county employees on Wednesday had stockpiled supplies for further attacks.
San Bernardino Police Chief Jarrod Burguan said in a press conference Thursday investigators found 3 pipe bombs combined into one unit at the Inland Regional Center with a remote control detonation device that “appears not to have worked.”
Officials found another 12 “pipe bomb-type devices” in the house and garage that became a focal point in the investigation, along with “hundreds of tools” to construct improvised bombs. Police also found 2,000 9mm and 2,500 .223-caliber long rifle rounds in the search.
Four high capacity “assault-style” guns recovered were all purchased legally, he said. Burguan said the number of wounded has risen from 17 to 21, with two police officers injured in the shootout on a black SUV that left two suspects dead.
Police are “confident” Syed Rizwan Farook, 28, and Tashfeen Malik, 27 – who were identified as the suspects killed after a police pursuit – are the same suspects in the shooting, a connection not previously confirmed.
Police found 1,400 .223-caliber rounds and over 200 9mm rounds on the suspects’ bodies. Twenty-three officers fired some 380 rounds at the SUV, and the suspects fired 76 rounds, hitting one officer in the leg.
A witness tipped off authorities to Farook, who officials learned had days before rented a black Ford Expedition, which was scheduled to be returned on the day of the shooting.
Burguan said while the motive behind the massacre is not yet known, the shooting was an “elaborate scheme” that appears to have included “a degree of planning.”
The couple arrived wearing tactical-style vests to hold ammunition and gun magazines, firing 65 to 75 into the room where San Bernardino County Department of Public Health officials were gathered for a holiday party.
Reports from witnesses indicate Farook had been at the event earlier, before he left and later returned to carry out the attack. But accounts vary on whether he left the party angry or “under duress,” or simply left without mention, Burguan said.
Asked if the couple had a target for the attack, the chief responded: “Well, they sprayed the room with bullets.”
David Bowdich, FBI assistant director in charge of the Los Angeles regional office, said Farook was a U.S. citizen born in Illinois. Malik held a Pakistani passport and was in the country on a K-1 visa, issued to allow fiancés to enter the country.
Both had previously traveled to Pakistan, and Farook re-entered the country in July 2014, he said. The couple had a child together.
But Bowdich said it would be “irresponsible” to call the massacre terrorism at this stage of the investigation.
Law enforcement plans to begin releasing the names of the victims later today.