The ACLU has filed another lawsuit against the city of St. Louis for its treatment of protests — but this one predates the unrest that's broken out in the city in the last two weeks.The suit, filed today in federal court, alleges that police shot tear gas and pepper spray at protesters who'd gathered in north city's Fountain Park neighborhood to protest the killing of Mansur Ball-Bey.
The eighteen-year-old was shot by police on August 19, 2015, after he ran from a house where officers were delivering a search warrant.…