According to police, two plainclothes detectives spotted the replica handgun, identified themselves as officers and approached the boy. Authorities say the boy then ran and the officers pursued on foot, shooting him at the end of the chase. From The Baltimore Sun:
[Baltimore Police Commissioner Kevin] Davis said he had “no reason to believe that these officers acted inappropriately in any way,” saying the officers did not know whether the weapon was a gun or a replica.
Davis also confirmed that the boy’s mother was taken in for questioning. He told reporters at the scene that “she knew” that he had left their home with the replica weapon.
“Police officers don’t take days off,” Davis told reporters.