A mother has filed a federal lawsuit after her 14-year-old son got into a fight at a school bus stop and was later shot to death by a police officer while the her son was hiding in a shed.

The lawsuit, filed by Denys Lopez Moreno against the Northside Independent School District of San Antonio, the district's Chief of Police John Page and school district police officer Daniel Alvarado, seeks punitive damages for civil rights violations, supervisory liability and negligence.

According to the lawsuit, Moreno's son, Derek, got into a fight with another boy at a school bus stop and punched him once. Alvarado witnessed the incident and ordered Derek to "freeze."

But instead of freezing, Derek ran, causing Alvarado to lose sight of him. Derek ended up jumping over a fence and hiding in a shed in the back yard of a nearby house.

The homeowner saw Derek enter his shed, called 911, and then flagged down Alvarado while he was driving around, searching the neighborhood.

In violation of police department procedures, according to the lawsuit, Alvarado drew his weapon immediately after exiting his patrol car, rushed into the back yard, and shot Derek within seconds of arriving at the house.

"When the homeowner heard the shot, she ran to the patio window facing the back of the house," the lawsuit states. "There she witnessed Alvarado carry the boy from the shed and lay him in the grass outside the shed door. She ran outside and saw Alvarado hovering over the boy who was moaning and thrashing in pain."

Derek died in an ambulance about 50 minutes after Alvarado shot him.

"Alvarado did not have a reasonable belief that he or any other person was in danger of imminent bodily harm," the lawsuit says. "Consequently, shooting and killing Derek was unwarranted under these circumstances, and was objectively unreasonable under the circumstances."

The lawsuit also claims the district acted with "deliberate indifference" by keeping Alvarado, who had been reprimanded sixteen times, on its police force without remedial training.