Green’s Dictionary of Slang

(US und.) in a pickpocket gang, that member immediately adjacent to the actual pickpocket, who takes the stolen item from him or her, and then passes it on to a third confederate to take away.

1867

Nat. Police Gaz. (NY) 26 Oct. n.p.: When the ‘wire’ has taken the pocketbook he passes it to the ‘coverer’ and the ‘coverer’ to the square bloke’ whose business it is to walk quickly off .