Vincent Bugliosi (August 18, 1934 to Juny 6, 2015) was an American attorney and prosecutor who among others prosecuted the so-called Charles Manson Family. 

This signature was obtained from the Backporch Tapes collection. 
The front of the postcard is addressed to the Manson Family. Bugliosi signed and the returned the card, at which time they removed the mailing label they had originally affixed to reveal that the card is addressed to "The Charles Manson Family" with the address to Spahn's Movie & Horse Ranch in Chatsworth, CA postmarked Jun 27, 2006.
Bugliosi has written and signed, My best wishes always, Vince Bugliosi.