Books like Nightlines by John Lutz

Her twin sister Jenine had been murdered, and Jeanette Boyington wanted St. Louis-based private eye Alo Nudger to help find the killer. Nudger knew he shouldn't take the case, knew it wasn't a good idea to get involved in an active police investigation. But he needed the work, and so he agreed to take it—and soon found himself caught in a web of deceit and danger.A murderer is stalking the streets of the Gateway City, and the only connection between his victims are the nightlines—special phone lines used by the phone company to test equipment. At night, lonely people use them to make contact with each other: to talk, to meet, perhaps, to have someone who will care, even if just for a moment, anonymously. But something has gone horribly wrong, and people are dying.Nudger is part of the network now, and discovers the very special lure of the nightlines when he falls in love with a woman he meets over them. A woman who may be the next victim...

First publish date: 1984