"στον κατεργάρη, κατεργάρης και μισός", όπως νομίζω ότι υπάρχει σχετική παροιμία (αν και βγάζει ελάχιστες γκουγκλιές).
Μου θύμισε ο sarant ότι δεν έχω κάτι γι' αυτό το set a thief to catch a thief. Σε αρχαία επιγράμματα υπάρχει το φωρὸς ἴχνια φὼρ ἔμαθον (φωρ = κλέφτης). Ιδού από το Oxford Dictionary of Proverbs:
- As they say, set a fool to catch a fool; a Proverb not of that gravity (as the Spaniards are), but very usefull and proper. [1654 E. Gayton Pleasant Notes upon Don Quixote iv. ii.]
- According to the old saying, Set a Thief to catch a Thief. [1665 R. Howard Four New Plays 74]
- ‘You have all your life been evading the laws. ‥Do you think this has qualified you peculiarly for being a guardian of the laws?’ Sir Terence replied, ‘Yes, sure, set a thief to catch a thief is no bad maxim.’ [1812 M. Edgeworth Tales of Fashionable Life VI. 446]
- A pickpocket specialist with the Washington Metro Transit Police Department says it may take a thief to catch a thief, but cops who are trained to think like crooks can do just as well. [2002 Washington Times 13 Jan. A9]