The gunman of a May shooting that killed 10 people at a supermarket in Buffalo, New York, has pleaded guilty to first-degree murder and other state charges, including domestic terrorism motivated by hate. Prosecutors say 19-year-old Payton Gendron was accused of carrying out the attack, which also wounded three other people, with the intention of killing as many African Americans as he could. Families of the victims spoke after Gendron's plea.