UPDATED Syed Rizwan Farook (pictured inset), who is U.S.-born, and Tashfeen Malik, 27, were killed in a gun battle with police after the mass shooting at a government holiday party held at the Inland Regional Center in San Bernardino. Relatives have said the two were married. San Bernardino Police Chief Jarrod Burguan said Farook, 28, an environmental specialist with the county health department, had attended the party, but left 'angry'. He said a motive is not yet known, but said there did seem to be 'some degree of planning involved' in the attack. He added Farook and Malik were in a relationship, but is it not clear if they were married or engaged. Farook was an environmental specialist with the county health department who sometimes worked at the Inland Regional Center. Farook had reportedly recently traveled to Saudi Arabia, where he married a woman he had met online. Hussam Ayloush, executive director of the Council on American-Islamic Relations (CAIR), says the couple left their baby with family Wednesday morning and never returned. Farook's brother-in-law Farhan Khan spoke at a press conference held at the offices of the CAIR in Anaheim to say he was stunned to hear of his relative's involvement in the shooting. Khan, who is married to Farook's sister, said he last spoke to him about a week ago. He said he had 'absolutely no idea why he would do this. I am shocked myself.' MORE:  'Devout' US citizen and his Saudi wife left their baby at home to storm office holiday party with automatic weapons and slaughter 14 of his colleagues before dying in bloody police shoot-out

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