Richmond, Va., police have arrested a 16-year-old and charged him with murder in the death of an 8-year-old boy.

Initially, detectives were given information that the suspect was an adult white male with scraggly facial hair, but later determined the victim had been threatened and intimidated by the suspect, who is a teenage black male. Detectives identified and located the suspect and took him for medical evaluation before being charged with the crimes.

The victim, 8-year-old Martin Cobb, was defending his 12-year-old sister from the alleged attacker, who was trying to sexually assault the girl. The suspect struck and killed Cobb on train tracks behind the children’s home.

The suspect also faces a charge of strangulation in connection with the assault on the girl.

The family told NBC News that the girl was being treated at VCU Medical Center and was feeling “ok.”

A vigil is planned for Saturday night at 7:30 p.m. at the Abundant Life Church in Richmond.