Police are investigating Michael Brown's stepfather for angry comments made to a Ferguson crowd after a grand jury decided not to indict the police officer who fatally shot his stepson.

St. Louis County Police spokesman Brian Schellman said Tuesday that police want to talk to Louis Head about his comments as part of a broader investigation into arson, vandalism and looting that followed the Nov. 24 grand jury announcement. Twelve commercial buildings were destroyed by fire.

Widely-circulated video showed Brown's mother, Lesley McSpadden, on top of a car and breaking down as the announcement blares on a stereo. Head, her husband, comforts her then repeatedly yells angry comments, including "Burn this bitch down!"

Family attorney Benjamin Crump has called the reaction "raw emotion," but "completely inappropriate."