catch someone red-handed

catch (one) red-handed

To see, and perhaps apprehend, someone as they are doing something (often something nefarious). The phrase might have originally referred to blood on a murderer's hands. The police caught the robbers red-handed as they ransacked another house. Timmy tried to get into the cookie jar again, but I caught him red-handed.
See also: catch
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

catch someone red-handed

COMMON If you catch someone red-handed, you see or find them while they are doing something illegal or wrong. The burglar was on the roof and was caught red-handed by the police. They all pleaded guilty to conspiring to import drugs after being caught red-handed by customs officers. Note: The reference here is to a guilty person whose hands are covered in blood.
See also: catch, someone
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012
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