Cases challenge no-parole terms for young adult killers

U.S. Supreme Court rulings and state laws in recent years have limited or banned sentences of life without the possibility of parole for people who commit crimes as juveniles because of the potential for change

BOSTON -- They were convicted of the same crime: the 2011 killing of a Boston teen as part of a gang feud. But Nyasani Watt — who pulled the trigger — will be able to fight for his release on parole after 15 years because he was only 17 at the time of the killing. Sheldon Mattis, who was just eight months older, was ordered to spend the rest of his life behind bars. U.S. Supreme Court rulings and state laws in recent years have limited or banned the use of life sentences without the possibility of parole for people who commit crimes as juveniles because of the potential for change. Now, research showing that the brain continues to develop after 18 is prompting some states to examine whether to extend such protections to young adults like Mattis, who say they too deserve a second chance.