In Flagrante Delicto
Red-handed; in the very fact. “Il a été pris en flagrant délit”, i.e. “Sur le fait.”
In for a Penny in for a Pound
I may as well “be hung for a sheep as a lamb.” If the punishment is the same, then it is worth the risk to commit the offence which brings the greatest profit.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on In Flagrante Delicto from Infoplease: