WEST ALLIS, Wis.—The investigation into 11 of the violent incidents on the opening night of the Wisconsin State Fair has resulted in the arrest of a 16-year-old African-American who reportedly told investigators he targeted whites.

West Allis police said Thursday the teen was arrested late Wednesday. The Milwaukee teen was booked on suspicion of attempted robbery and robbery. Police recommend that he face additional penalties for hate crimes.

Police say the teen told investigators whites were chosen because he considered them “easy targets.”

On opening night of the fair last week, 31 people were arrested and at least 11 people were hurt. The West Allis Police Department has said race was a factor in the 11 violent incidents it’s investigating.

The State Fair has stepped up security since the attacks.