US mobster (2,6)

I believe the answer is:

al capone

(Other definitions for al capone that I've seen before include "US gangster in Chicago, arrested for tax evasion" , "Famous gangster" , "Notorious gangster, d. 1947" , "Notorious Chicago gangster nicknamed Scarface" , "Chicago mobster jailed for tax evasion" .)

I've seen this clue in The Guardian.

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