Green’s Dictionary of Slang

(US Und.) an arrest on false or petty charges.

1931–4		D. Clemmer Prison Community (1940) 333/1: hummer, n. An arrest on a false charge; a ‘bum rap.’.
1949		Monteleone Criminal Sl. (rev. edn).
1950		Goldin et al. DAUL 104/1: Hummer. An arrest on a charge of which one is innocent; a bum rap; a stiff; a phony rap.
1970		J. Wambaugh New Centurions 187: ‘She mentioned the cute [...] cop that booked her on a hummer. She claims she laid a hand on your knee and you pinched her for lewd conduct ’.
1971		H.E. Roberts Third Ear n.p.: hummer [...] 3. a ‘bum rap’.
1975		E. Torres Carlito’s Way 126: I’m here on the fly [...] caught up in the web on a hummer.