Man kills mistress after she admits to being HIV positive.

Larry Dunn admits to police he killed his mistress to get revenge.

"I wanted to make her pay," Dunn said in a recorded interview with police according to the Dallas Morning News. "Killing her wasn't on the menu. That's just how it ended up."

Dunn, 37, was cheating on his wife with a woman named Cicely Lee Bolden — who in September 2012 told Dunn she was HIV positive.

A week later Dunn went to her home in Dallas to exact revenge, but not before having unprotected sex one last time, the Morning News reported from his murder trial this week.

As Bolden was lying in her bed, Dunn went to the kitchen and grabbed a steak knife. He then went into the bedroom and stabbed her in the chest, according to a confession the Morning News reported was played at his murder trial this week.

"In my mind, I'm already dead," Dunn said in the video. "She killed me, so I killed her."

Dunn, who said he had unprotected sex with Bolden one last time because it wouldn't matter, also said his lover did not have a chance to defend herself, the Morning News reported.

"She didn't see it until it was in her throat," Dunn told police. "She wasn't very strong."

Dunn's attorney said his client is still undergoing tests to determine if he contracted the disease. He faces life in prison but his sentence would stretch from two to 20 years if jurors rule he acted with "sudden passion," the Morning News reported.