The shooting injured several people and killed 22-year-old Jared Martinez.
Maestas-Reza was arrested on an unrelated juvenile parole violation on Feb. 22 and placed at the Grand Mesa Youth Services Center.
During his incarceration, GJPD detectives continued to work on the homicide investigation and obtained an arrest warrant on Wednesday.
He was remanded to the Mesa County Detention Facility and is accused of first-degree murder along with additional charges.
The warrant in this case has been sealed and no further details are available for release, the police department said.
According to initial information released after the shooting occurred, officers believed it to be a targeted incident.
An 11-year-old child has been charged with murder for shooting and killing a woman, 62, in Colorado.
The young person, who has not been identified, is charged with second-degree murder following the death of Karmen Keefauver in Montrose County.
Officers and first responders were called to a property on December 19 after they received a report that a woman had been shot.
They took Keefauver to Montrose Memorial Hospital where she later died, The Denver Channel reports.
An 11 year old has been charged with second-degree murder after 62-year-old Karmen Keefauver was shot dead. Pictured: The home where Karmen was found in Montrose County