A Chicago boy accidently shot and killed his 3-year-old brother while playing with his father’s illegal gun on Sunday. The boys were playing a common game known as “cops and robbers” and got ahold of their father’s gun who told officials was given to him illegally by a gang member in Chicago.

The boy was rushed to the hospital but later died.

Police arrested the boys’ father, 25-year-old Michael Santiago, on a felony charge of child endangerment. The gun was reportedly bought off the street, kept on top of the refrigerator wrapped in pajama pants, and was shown to the oldest son. Being a former gang member himself, the father kept the gun for protection after he knowingly snitched on another gang member in a murder trial.

Santiago is represented by the county’s public defender and has bail set at $75,000.