SA councillor chases down rock thrower

A councillor has chased down a man after a rock was thrown through a council building window during a meeting in Adelaide.

The Campbelltown City councillor caught the 31-year-old after he smashed the window and fled on Tuesday night, police allege.

No one was injured and the accused was reported for property damage and will be summonsed to appear in the Adelaide Magistrates Court at a later date.