Locked up for life at 15, Norman Brown remains defined by the crime that put him behind bars. Twenty-seven years ago, Brown joined a neighbor twice his age to rob a Chesterfield, Mo., jewelry shop, and the man shot the owner to death. The shooter was executed. But state officials, bound by a 2016 Supreme Court ruling, pledged to give Brown an opportunity for release — then rejected parole in a process a judge ruled recently must be overhauled. Three years after the Supreme Court gave inmates like Brown a chance at freedom, about 400 offenders sentenced to life without parole as juveniles have been released nationwide and hundreds more have gotten shortened sentences.