Police said the teen was arrested without incident Wednesday night at a home in Albuquerque.
Police said previously that Jose Hernandez was shot Monday while intervening in a dispute between the 17-year-old and his mother in front of the mother’s home.
The Associated Press does not generally identify juveniles accused of crimes.
It’s not immediately known whether the boy has a defense attorney who could comment on his behalf.
Hernandez had worked for the U.S. Postal Service in Albuquerque for 12 years.