red-handed 
adjective
Used to indicate that a person has been discovered in or just after the act of doing something wrong or illegal: I caught him red-handed, stealing a wallet...
- He spends all of his waking hours hatching schemes to catch the thief red-handed.
- Armed robbers were caught red-handed yesterday as they were about to carry out a raid on a security van.
- Of course, the police caught the burglars red-handed.
Synonyms
in the act, with one's fingers/hand in the till;
Latin in flagrante delicto
informal dead to rights
British informal bang to rights
with one's trousers down
North American informal with one's pants down
Rhymes
- single-acting
- single-action
- single blessedness
- single-blind
- single bond
- single-breasted
- single carriageway
- single-cell protein
- single combat
- single-copy
- single cream
- single currency
- single-cut
- single-decker
- single digging
- singledom
- single-elimination
- single end
- single-ended
- single-entry
- Single European Act
- single European currency
- single file
- single-foot
- single-handed