Richard and Nancy Lyon

Three witnesses provided what many observers judged to be damning testimony.

The first was Dr. Ali Bagheri, a third-year resident at Presbyterian Hospital who treated Nancy.

Bagheri testified that before she slipped into a coma, Nancy Lyon described to him the wine and movie theater incidents. He said she implicated her husband, whom she feared had poisoned her. He said he had never considered intentional poisoning as a diagnosis until Nancy spoke to him that morning.

In his testimony, the doctor also recited for the jury the woman's last words: "Please don't let me die."

Charles Couch

The second damning witness was directly related to Richard Lyon's sleuthing.

Lyon had testified that it was Nancy's idea to use arsenic against the fire ants, and he said he found a receipt in her personal papers to prove it. The receipt, on the letterhead of Chemical Engineering, a Texas industrial cleaning firm, was for the purchase of arsenic trioxide, among other things. It was signed by Nancy Lyon.

The defense team tracked down and subpoenaed the owner of the firm, who told a long story on the witness stand about how a woman had called him to ask for advice in eradicating fire ants.

He drew up a list of chemicals — as advice, not as part of a sale — and the woman came in to his office to pick it up.

But when defense attorney Guthrie asked the witness, Charles Couch, to identify the receipt, he declared it "a total counterfeit."

Someone had copied and enlarged the letterhead from the Chemical Engineering notepad on which he had jotted his suggestions, and then pasted it atop a standard lined receipt form. The chemicals that Couch had suggested were listed on the receipt as though they had been purchased by Nancy Lyon, whose signature appeared on the form.

The defense had expected Charles Couch's testimony to set Richard Lyon free.

Instead, it set him squirming in his seat.

Prosecutor Sims asked Couch to describe the woman who picked up his tip sheet.

He said he hadn't seen her, but added, "My man said that she was a blonde."

Nancy Lyon was brunette. Tami Lyn Gaisford was blonde.

The third damning witness was a handwriting expert. He testified that his analysis indicated that either Richard or Nancy could have written the Chemical Engineering receipt.

But he was certain about the incest passage on the woman's counseling notes.

That portion was written by Richard Lyon, he said, adding, "It is my unqualified opinion."