Behind the Devil's Mirror - Richard J. Johnson - Bog

After cutting short a vacation with difficult relatives, Paul and Cindy Jason take the scenic route home to Chicago. On impulse, they stop at a farm auction where they meet the owners, Melvin and Minnie Link. Cindy admires an old, hand-carved mirror that comes with an eerie history. For a mere ten dollars, Cindy is the new owner of this unusual mirror that Melvin claims is at least 120 years old. But the Jasons quickly discover that the mirror is no bargain.
From the moment the mirror is hung in the apartment, a certain pall hangs over them-and soon it's making them both a little crazy. With the help of Cindy's sister and brother-in-law, the four are unwittingly drawn into a frightening and macabre doorway into another world-the world of the dead, commonly referred to as purgatory.

Three decades earlier, a greedy and treacherous character invaded the lives of Minnie and Melvin Link. Unexpectedly granted a supernatural power over the Jason's minds, Minnie attempts to communicate her desperate plight to them with terrifying and unforeseen consequences, and the four find themselves embroiled in an attempt to find justice for the victims of an unsolved thirty-year-old murder.