In addition to going on a shooting rampage, investigators say the San Bernardino shooters may have also planned to kill first responders with a self-detonating bomb.

Syed Rizwan Farook and his wife, Tashfeen Malik, caused havoc on Dec. 2, when they opened fire at the Inland Regional Center during a Christmas party, leaving 14 people dead and 21 others wounded. Both suspects were killed in a shootout with police after the attack.

Following the attack, investigators found a "suspicious device" that was left behind in a conference room at the center to possibly cause more damage. The device was made up of three bundled pipe bombs and remote control car parts, which were hidden inside a canvas bag, said San Bernardino Police Chief Jarrod Burguan, according to The Sacramento Bee.

Officials say the device resembled the same type of crude explosives that the al-Qaeda magazine "Inspire" advises their supporters to build for planned terror attacks.

"It was designed that the remote-controlled device would somehow trigger or set that device off," Burguan said. "We don't know if they attempted to do that, and it failed, or what the story is."

Through radio chatter, police mentioned a "suspicious device" in or near the conference room where the attack occurred, reports The Los Angeles Times. "We need to slow things down," said an officer after the device was located. "I need you to advise all the units to move with caution."

Bomb technicians, however, do not believe the device would have actually detonated, said an unnamed law enforcement official. Instead, it is likely that the device would have malfunctioned due to the building's sprinkler system, which was activated during the shooting, and water damage, said the source.

On Saturday, ISIS hailed the shooters as their "supporters," but the group did not take responsibility for the attack, nor did they say that the couple was part of their network, reports CNN.

"We pray to God to accept them as martyrs," ISIS' al-Bayan Radio declared.