Free again from the author via KDP Select @ Amazon: (individual linkage, since the author's name is common enough to bring up a bunch of unrelated titles)
Secrets by Michael A. Smith, a dark side of suburbia murder suspense thriller originally out from St. Martin's Press in 1980.
Frank Montgomery and his family love their life in the placid suburb of Lake View. Members of the seven households on Horseshoe Drive form an extended family. Like any family, they occasionally play practical jokes on each other. But the harmless pranks suddenly turn ugly, even obscene. Feelings become heated, alliances form, fingers are pointed--until a brutal murder ends the life of the prime suspect. Frank digs deep into his neighbors' lives and discovers that motives for the murder abound. Secrets reveals a dark side of suburbia. It's enough to make you wonder about your neighbors. Who are they really? What are they up to? Are you watching them? Are they watching you?
Legacy of the Lake, a crime/corruption mystery adventure thriller originally out from Avon in 1980.
Jack Olsen, a down-on-his luck former cop, seeks inner healing at the Lake of the Ozarks in Missouri. Out fishing one day, he witnesses a deliberate collision that leaves one man dead. Hired by the elderly victim's companion to investigate the so-called accident, Jack discovers another world beneath the surface of paradise---one characterized by organized crime, political corruption, drugs and gambling. Working with Kate Carter, the new love of his life, Jack follows a money trail littered with greed, obsession and hate. With one final throw of the dice, it appears he's turned up snake eyes.
Smith also offers a repeat of his Jeremiah Trilogy of sfnal technothrillers involving an extremist separatist religious cult originally out from Tor's Forge imprint,
x-linked in the SF/Fantasy megathread.