On January 14, 1980, Sophie Barrera walks to her car outside a medical building in St. Louis. As she keys the ignition to her Pinto, dynamite attached to the underside of the car detonates, killing her instantly. Sophie's son, Frederick Barrera, accuses Glenn Engleman, a dentist who owes Sophie Barrera's dental lab over $14,000. The authorities are perplexed; Glenn Engleman is a hard-working neighborhood dentist who only charges customers what they can afford to pay. He hardly seems like the kind of man who would kill people for money. But Ruth Engleman, the suspect's ex-wife, paints a very different picture of the kindly dentist. As she tells FBI agent William McGarvey, that Dr. Engleman is responsible for seven murders and Ruth is afraid she will be next. Ruth agrees to have her condo wired with microphones but try as she might, Ruth can't get Engleman to talk about the murders. She resorts to having sex with him before he opens up. The FBI finally has enough to arrest Engleman. At trial, a jury deliberates just 12 hours before sentencing Engleman to life in prison. He avoids the death penalty by confessing to the murder of the Gusewelle family.