The New York City Police Riots
… The arrest of Mayor Wood was ordered. Captain Walling of the Metropolitan Police was sent to arrest the Mayor but was promptly thrown out on his ear. Wood occupied City Hall protected by 300 of his Municipals who resisted a force of 50 Metropolitans sent there to arrest him. Later that day 50 Metropolitan Police descended on City Hall with night sticks in hand to carry out the order. The Municipals ran into the street and the two factions fought each other. The Metropolitans retreated. 52 policemen were injured, one crippled for life. The Metropolitan Police Board then called in the National Guard who surrounded City Hall. The Mayor finally submitted to arrest but soon returned to office released on minimal bail.
From Ubanography, but I didn’t believe it, until I found confirmation at the official website of New York City.
I’m really tickled to know that New York had two rival police forces. Thanks to Ian Goldberg for mentioning it.