City officials previously withheld identifying the 16-year-old, who was an employee at the Virginia Walmart, "due to him being a minor."
Police identified Chavez-Barron following a vigil on Thursday honoring all the victims killed by 31-year-old Andre Bing, an overnight team leader at the Walmart store who had been with the company since 2010.
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Family, friends and classmates of Chavez-Barron gathered by a tree close to the store's front entrance and recited the prayer Hail Mary on the rosary in his memory, NBC affiliate WAVY of Portsmouth reported.
Authorities say Bing killed at least six people and injured at least six others before taking his own life in the Tuesday night shooting.