Yvette Willard found her husband's lifeless body in the garage. By his side was a note apologizing for leaving his family and also denying his involvement in Eric Miller's murder.
"I have been accused of an action for which I am not responsible," Derril wrote. "I have taken no one's life save my own."
Yvette says her husband was supposed to see his lawyer that day. She says he was worried that morning after the police searched their home looking for arsenic. Stories about his affair with Ann - his romantic trip to Chicago with her just days before Eric fell ill at the bowling alley - were going to be all over the news.
Yvette already knew what the world was just finding out about her husband's affair. She says she had her suspicions for weeks.
"I knew he was attracted to Ann when I knew the way he talked about her versus the way he talked about everybody else at work," she says.
Before Ann, Yvette says Derril had been depressed, trying to take stock of his life as he approached 40. "We had been married for awhile," she explains. "The newness has worn off and we just started, you know, fighting a little more."
But after he became friendly with Ann, Derril began paying more attention to his appearance and working out. On Yvette's birthday, Derril told her he needed some time away to think things over.
"I knew what he was going out of town for," she says. That was the weekend in Chicago with Ann Miller. Yvette says she didn't confront her husband out of "fear."
"You can know the truth, but until it's spoken, once you those words get out, you can't get them back. And I guess I was hoping he'd realize what he was doing," she tells Troy Roberts.
But after Eric's murder, Derril sat Yvette down. "He said he didn't know if he loved me and that he had been having an affair. And I said 'With Ann.' He said, 'Yes.'"
Roberts asks her, "What do you think was going through his mind? Did he think he had a future with this woman?"
"I think that Derril would not have had an affair without that," Yvette replies. And when asked if Derril put arsenic in Eric Miller's beer that day she says, "I do not believe so." Yvette says she asked her husband that very question, to which he said, "No, I didn't."
Yvette says Derril would not have tried to kill Eric, because he "wasn't the type that thought he could get away with something like that."
Yvette says Derril is just not capable of murder, that he would have encouraged Ann to seek a divorce - not help her kill her husband. And although he was innocent, she says her husband was emotionally fragile and could not bare the very public accusations.
"He had made one comment to me prior to his death. He said, 'You know how to bend. You can take things. And you just bend and you keep going.' He says, 'I can't. I'll break.' And so I knew he just couldn't cope anymore."
Yvette's last conversation with her husband took place the day after the house was searched.
"I told him it was gonna be a really hard day and I asked if he'd give me a hug. And he did. And I thought he was gonna break my bones. He was squeezing... and then I left."
While Yvette dropped their daughter at daycare and headed in to work, Derril was planning his death.
"The world looks black to me," he wrote. "All I can see is the smearing of my name, pain caused to my family, personal humiliation and probable economic ruin."
Derril thought his family would be better off without him. Yvette blames Ann Miller for his death. "My husband would still be here if it wasn't for her."
The Millers, on the other hand, didn't know what to believe.
"Ann was feeding us information such that Derril was obsessed with her..." says Eric's sister, Leeann. "We did think that it was possible that Derril poisoned Eric and in the end was trying to get him out of the picture."
But when the full autopsy report was released, the Millers were flabbergasted.
"I think it's likely that Eric received at least one dose of arsenic in the hospital. And very likely, the fatal dose," says Medical Examiner Dr. Tom Clark.
Incredible as it sounds, Dr. Clark is almost certain that someone came into Eric's hospital room and finished him off with a final fatal dose. But that wasn't the only stunning news.
To the shock of investigators, Dr. Clark's team found arsenic in Eric's hair four months before he went bowling with Derril Willard and months before police believe Derril and Ann began their affair.
"Arsenic's not the kind of crime you can commit at any distance," Morgan explains. "You have to be able to put the arsenic in the food or drink and introduce into the body."
In terms of possible suspects, that left only Ann. Morgan believes she dosed her husband with arsenic for months. "I do think that Ann was seeing just how much poison it would take to make Eric sick, sort of experimenting," he says.
And then, Morgan says, Ann turned to Derril. "Ann reached a point where she was ready to eliminate Eric," he explains. "She needs to make sure that she keeps her hands clean and has a reasonable patsy, that if something does goes wrong, he can take the fall."
If Ann really was this cold and calculating, was she in fact a psychopath? Morgan and the Millers feared the worst. Would she now try to hurt baby Clare?
"I am scared to death for Clare's well being," says Leeann. "You know at any moment she could be poisoning Clare."