Meaning
To be caught in the act of committing a misdemeanour, with the evidence there for all to see.
Origin
caught red-handedThe Red Hand has long been a heraldic and cultural symbol of the northern Irish province of Ulster. One of the many myths as to its origin is the tale of how, in a boat race in which the first to touch the shore of Ulster was to become the province's ruler, one contestant guaranteed his win by cutting off his hand and throwing it to the shore ahead of his rivals. The potency of the symbol remains and is used in the Ulster flag, and as recently as the 1970s a group of Ulster loyalist paramilitaries named themselves the Red Hand Commandos.