Though there's some impressively up-to-date material on cable-TV here, this third outing for TV-network troubleshooter Matt Cobb centers on a domestic murder-mystery unconnected to Matt's job. The throat-battered victim: upstate-N.Y. heiress Debra Whitney, who was about to marry a preppy swain after jilting longtime lover Dan Morris (Matt's old college-chum) for the umpteenth time. So karate expert Dan--who was heard to say ""I'm going to stop that marriage if I have to strangle her!""--is the prime suspect. And Matt, upstate for hearings on cable licensing (he suspects a bribery seam), decides to clear his pal's name, with help from lawyer Eve (an old, rekindled flame) and the loyal assistants up from N.Y.C. Unfortunately, there are only one or two other possible culprits--and it's easy to spot the killer. But Matt is a bright, if occasionally smirky narrator; the cable-TV crisis (which echoes the recent demise of CBS Cable) is a strong subplot, with Matt pursued by a thug he calls ""The Organic Hit Man""; and, while not in a class with DeAndrea's Killed in the Ratings debut, this is livelier going than the labored followup, Killed in the Act.