A California gun statute going into effect on 1 January gives the police or family members the option to petition the courts to seize the guns and ammunition of someone they think poses a threat, the first law of its kind in the country.
http://www.theguardian.com/us-news/2015/dec/31/landmark-california-gun-seizure-law-takes-effect
http://www.theguardian.com/us-news/2015/dec/31/landmark-california-gun-seizure-law-takes-effect