On October 24, 1871 a police officer responding to shots fired entered a notoriously bad area of Los Angeles to find a Chinese man shot in the neck. He saw men fleeing the scene and followed them into a building. He was then shot in the shoulder. Hearing his cries a local business owner also rushed into the same building, after firing several shots into it. He too was shot his injury much worse, he died an hour later.
Soon a mob developed and started to lay siege to the building the fleeing men were held up in. 17 Chinese were hung from the local wagon shop roof.
This was the largest mass lynching in American history and I bet, like me, you have never heard of it. Thank you to Christian P. who brought this to my attention. The whole article can be found on laweekly.com.
This story is not over yet. It was later revealed that the officer that went to investigate the shots may have actually been going to rob from a rich Chinese business man. The officer turns out to be not such a great guy, many court cases were filed against him. For example some accused him of stealing valuable roosters to fight in his cockfighting side business. The officer was also a gambler and believed to be manipulating the voting. This thing is so screwed up! Eventually, several people are brought to court for the charges, but the case gets thrown out. Unbelievable.
The story gets better, and it is amazing that there has not been a book published about this incident yet. There is a chapter on it in A Companion to Los Angeles (Blackwell Companions to American History). You can read some of the chapter in this book by googling The Anti-Chinese Massacre of 1871 Victor Jew the 5th link down is a link to the google book preview.
Image credit: Marion Doss unrelated image of lynching.