Green’s Dictionary of Slang

1. (US Und.) to swindle by promising some variety of illegal pleasure, usu. sex, then taking the money and failing to deliver the promised ‘goods’.

1965		C. Brown Manchild in the Promised Land (1969) 324: I started teaching him the street life. I taught him how to Murphy.
2002		‘Touré’ Portable Promised Land (ms.) 67: Eddie Murphy, who often plays a contemporary urban trickster [...] has the good fortune of sharing his last name with traditional English: murphy is a word that means to con.

2. in a non-criminal sense, to leave without fulfilling a promise.

2005

J. Stahl I, Fatty 41: He’s murphied out on me.