How Did The Klu Klux Klan Get Away With Their Crimes?

Blacks were too scared and powerless to report it and whites were either in on it or were intimidated against reporting it. It wasn't until some brave people, black and white, christian, jew and muslim, stood up to the racist minority and took their freedoms back.

Black people were too scared to report the torture they were facing just incase they reported it to an actual KKK member.

It was a secret organization and members wore disguises when engaging in any illegal activities.

Through fear and intimidation. At the height of the KKK,  blacks did not have a voice or protection  against the KKK. It's a shameful footnote in history that people were hung due to their color.