Richard Lyon Trial: 1991-92

Before the jury was even seated, Lyon's attorney, Dan Guthrie, publicly characterized Nancy's death as "an honest-to-goodness Perry Mason-style whodunit." The statement hinted at Guthrie's defense to establish reasonable doubt. In the trial, Guthrie attacked local police for ignoring other possible suspects with motives much stronger than Lyon's. Among them: Nancy's older brother, who had sexually abused her in childhood; the Lyons' nanny, who disliked Nancy Lyon; and Nancy's former boss, who had been involved in a litigious, work-related scandal and may have wanted to keep Nancy quiet.

In the courtroom, the defense presented several other theories about Nancy's death. Couldn't this depressed incest victim have committed suicide, then framed her unfaithful husband in a final act of spite? Couldn't overworked emergency room doctors have administered drugs that caused fatal side effects? Wasn't it even possible that Mrs. Lyon had accidentally poisoned herself?

After all, there were plenty of toxic chemicals around the couple's fashionable Park Cities home. Lyon claimed Nancy was working with him to eradicate pesky fire ants mounds from their yard. The project, said Lyon, a professional landscaper, involved mail-ordering a series of chemicals to concoct a homemade ant-killing poison. In fact, Nancy herself had signed the receipt when arsenic trioxide and other chemicals were delivered to their home.

The prosecution whittled away at Lyon's defense with a series of condemning witnesses and a mountain of incriminating documents. Family nanny Lynn Pease-Woods testified that although she and Nancy Lyon had personal difficulties when she was hired in 1987, she eventually loved working for the Lyons. She visited the children after Nancy had quit her real estate job in 1990 to be home with daughters Anna, 3, and Allison, 5.

The nanny also testified that Richard over time had given his wife large "vitimins" from a bottle. The nanny turned the capsules over to detectives after Nancy's death. A toxicologist later testified that two of the pills in the bottle contained barium carbonate, a substance used in rat poison. Pease-Woods said that there were no major ant hills at the Lyon house.

The lead police investigator testified he found store-bought fire ant killer in the Lyons' garage. More damaging, the investigator said that when he questioned Lyon, he initially denied he had ordered any toxic chemicals. Pressed further, Lyon modified his statement.