After California changed its murder laws last fall, Neko Wilson was the first man to walk free.

Wilson, 37, had been facing the death penalty for a 2009 robbery that led to the deaths of a couple in Fresno County. No one accused him of killing anyone, or even of being in the family's home that night, but prosecutors said that he helped plan the break-in.

At the time, that was enough for him to be charged with felony murder, under a doctrine that holds that anyone involved in a crime is responsible if a death occurs. But in September,