LOS ANGELES (AFP) - Attorneys representing the family of the California mass shooters described the couple on Friday (Dec 4) as devout Muslims but said there was no sign they had become radicalised.

Syed Farook, 28, and his 27-year-old wife Tashfeen Malik died in a shootout with police, hours after killing 14 people at a year-end party organized by Farook's employer in San Bernardino on Wednesday.

"There is no sign that the alleged shooters belonged to a larger organization or a terrorist cell," Mr David Chesley, one of two attorneys representing the family, told a news conference.

The family's attorneys said the couple, who lived in a townhouse with their baby daughter and Farook's mother, were quiet and kept to themselves.

Mr Chesley said Tashfeen, who met Farook on an online dating site in 2013 and married him a year later in Saudi Arabia, was traditional and devout.

"There is very little information we have about her," he said, describing her as a "typical housewife".

Attorney Mohammad Abuershaid said few people came in contact with Tashfeen, who was born in Pakistan, wore the full-face veil and did not drive.

"The women (in the family) communicated with her. Farook didn't want anyone else to talk to her," Mr Abuershaid said. "She was very soft-spoken and nice."

When Farook's family members came to visit, he said, the women sat in one room and the men in another.

"This is a very traditional way of acting," Mr Abuershaid said. "So the men did not interact with her."

He said the men in the family had never seen Tashfeen's face as she wore the burqa, or full-face veil.

"They just knew her as Syed's wife," he said.

The attorneys said the family was aware that Farook had guns but didn't think much of that as he had acquired them legally and enjoyed target practice.

"As a gun owner myself, I probably have 4,000 to 5,000 rounds that I keep at home," Mr Chesley said. "And the reason we buy them in bulk, is they're cheaper that way."

He and Mr Abuershaid said Farook's family were interviewed for four hours on Thursday by FBI agents trying to piece together what prompted the carnage.

"If there's anything remarkable about the (interview) that took place yesterday, it is that no ties (to extremist groups) could really be established to the point of frustration on the part of the FBI," Mr Chesley said.

The FBI said the shooting, the deadliest in the country in three years, was being treated as an "act of terrorism" but there was no evidence yet linking the pair to a network.

He also appeared to downplay reports that Tashfeen had posted a message on Facebook around the time of the attacks expressing support for the leader of the radical Islamic State in Iraq and Syria group.

"The entire world is digging for information and the most we've gotten so far is somebody looked at something on Facebook," Mr Chesley said.