The incident occurred when the employees of county health department were attending a party at the Inland Regional Centre. More than 500 people were present at the centre when shooting occurred, police said.
After the shooting, the couple wearing "assault-style clothing" fled in a black SUV, leading to a lengthy police chase.
Hours later, the attackers were killed by police in an encounter.
Seventeen others were injured - mostly by bullets from automatic-style rifles. Some persons injured in the panic to escape, they said.
The deceased woman was identified by police as 27-year-old Tashfeen Malik and the man as Syed Farook, 28, a US citizen. Malik's nationality was not clear immediately.
"There was a shootout," a police official said.
"A device that looked like a bomb also flew out of the vehicle," local media reports quoted Meredith Davis with the Bureau of Alcohol Tobacco and Firearms and Explosives as saying.
He said that both the suspects were dressed in "dark, kind of tactical gear".
Relatives of the suspects have said the two were married. Farook was an environmental specialist with the county health department who sometimes worked at the Inland Regional Center in San Bernardino.
Burguan told reporters that Farook angrily left the office holiday party before returning with Malik.
Police believe that the man and woman killed in a gun battle were the only two shooters.
FBI officials were carrying out raids at an apartment in Redlands, where authorities were serving a search warrant connected to the shooting.
President Barack Obama was briefed about the shooting incident.
Soon after Farook's name became public, his
brother-in-law Farhan Khan called a press conference where he said he last talked to Farook a week ago.
"The reason I am here is to express [for] my family...How sad they are for what happened," said Khan, adding that he was very sad over lives lost in the shooting.
"I have no idea why he would he do something like this. I have absolutely no idea. I am in shock myself." Khan said when asked whether Farook was religious.
The US has witnessed over 300 incidents of shooting this year.
The incident marks the deadliest mass shooting in the US since 26 people were killed at a school in Newton, Connecticut in 2012.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
