Answer: The Klan in Mississippi, in particular, was after a 24-year-old New Yorker named Michael Schwerner. He’d been especially active in organizing local boycotts of biased businesses and helping with voter registration. On June 16, acting on a tip, a mob of armed KKK members descended on a local church meeting looking for him. Schwerner wasn’t there, so they torched the church and beat the churchgoers.
Explanation:
In the end, the Klan’s homicidal ways backfired. The murders galvanized the nation and provided impetus for the passage of the landmark Civil Rights Act of 1964 on July 2.
It could mean many things but the most common explanation is to own up to your mistakes. to not walk around looking for someone else to blame. It depends on how it's used in context though.