Origin
Evan Pepper is a health inspector for the state of New York, with territories concentrated around Williamsburg, Brooklyn. When he discovered a warehouse full of illegal chicken meat, he got grabbed by the henchmen and his finger got chopped off as a warning. But he never made it out of the warehouse, because he was killed by Mason Savoy to silence Evan Pepper.
The finger ended up in a burger, where it was discovered by Daniel Cornblum and given to Tony Chu, the FDA cibopath, to eat and solve the murder.