Bad Business / Robert B. parker / 310 pages / November Challenge Dead Authors

This is the thirty-first mystery starring the Boston private eye, Spencer.  Here Spencer is hired by one Marlene Cowley to conduct surveillance on her assumed cheating spouse.  While engaging in said surveillance, Spencer discovers that another private eye is shadowing Marlene.  Yet another investigator is discovered and one of the surveillance subjects is murdered.  Spencer is determined to discover the murderer, especially after he is offered a lucrative contract in Tulsa to remove him from the case... and the other two investigators go missing.  Spencer uncovers a surprising perpetrator and corporate greed.