Grayson served as a mechanic in the US Army for two years but was discharged in 2016 for serious misconduct.
A 15-year-old driver is being considered for transfer to adult court and has been charged with first-degree murder under accountability.
Police could not say yet whether anyone is in custody.
Due to the suspect's status as a juvenile, police refrains from disclosing their identity.
Johnson is currently detained at the Robertson County Jail.
The shooting suspect has not been arrested yet
The case will be presented to the Greene County Prosecutor’s Office for review.
Family members confirm that Lopez was a dedicated special education teacher at Nathan S. Davis Elementary School in Brighton Park.