Sin Snoop by John Dexter

'Orgy Assignment... it took a while before reporter Ed Benson guessed that he was being used as an instrument in a sinful scheme of sex. His job was to get photographic evidence for a shameless expose, and he had taken pictures that were brutally graphic--now he knew too much. Instead of a planned expose, the scheme was one of blackmail, a scheme to be climaxed by Ed's death... to stop the ...Shame Expose!'