The suspected San Bernardino attackers who killed 14 people in a gun rampage in California had 12 pipe bombs, weapons and thousands of rounds of ammunition at their home, a police raid on the premisis revealed following the massacre.
Two suspects, a man and a woman, who are identified as 28 year old Syed Farook and Tashfeen Malik, 27, his wife and mother of his 6-month-old daughter, were shot dead about four hours later in a gunbattle with police.
The attack took place in a conference area where the San Bernardino County Department of Public Health was holding a social event.
San Bernardino Police Chief Jarrod Burguan said that the number of wounded people has risen from 17 to 21.
Burguan also said that during the attack, they had two assault-style rifles, two semi-automatic handguns and 1,600 rounds of ammunition in their rented vehicle.
The FBI and authorities have initiated a thorough search to learn why they left their children behind and went on the rampage.
After the incident President Barack Obama reiterated his desire to end gun crime in the US.
"One thing we do know is that we have a pattern of mass shootings in this country that has no parallel anywhere in the world," he said.
"There are some steps that we could take, not to eliminate all incidents, but to make sure they happen less frequently."