A 15-year-old boy was killed after he accidentally shot himself while playing with a loaded gun at his friend's home Wednesday night.

The incident occurred inside a home on Williams Street around 8 p.m. 

Police say Derek Cosme and two of his friends were inside the house alone when they somehow got their hands on an unsecured handgun. 

Nassau police did not comment on who the gun belongs to. Neighbors say there are retired and active members of law enforcement living in the home. 

Relatives say the teen's mother just arrived at the home to pick her son up when she saw all the police activity. They say that's how she learned her son was dead.

Relatives describe Cosme as a quiet kid with a tight knit group of friends. He would have been a junior at Glen Cove High School in the fall. 

Nassau police say if it's determined that the weapon was not properly secured, the owner's license could be revoked. If a service weapon was involved in the incident, they say that person could lose their job.