"There was a group of us working and when we finished, I don't know what happened to her. All I can tell you is when she left the facility, was in tears, but nothing I did," Matt said.
"20/20" documented six other complaints against Matt: from a female custodian from the First Baptist Church of Waco, who says he grabbed her sexually; a teenage girl from the same church who claimed he spoke to her in a sexually provocative manner; and at the YMCA where he supervised the day camp, four young women complained to management of improper sexual conduct.
Matt denies all of this, including any claims of assault.
"I can say this and I'll say it again that ... never once did I solicit sex from anybody," Matt said. "But can there have been things that have been said that [were] misconstrued? Possible, but never once did I solicit sex from them."
What really turned Kari's family against him was the revelation that Matt had given Kari's cell phone to a young woman from his church whom he called every day. The police affidavit outlining Matt's arrest accuses him of having an affair with this woman and even claims they were seen shopping for engagement rings together. The affidavit states Matt's motive for murder was to continue this new relationship.
Matt claims the relationship was platonic and he and the young women were buying earrings for his daughters.
The police affidavit also claims Kari may have suspected her life was in danger. The affidavit says Kari believed Matt was having an affair and that she told her counselor she found crushed pills in his briefcase and was afraid he was going to poison her because he was having an affair. Police say they found evidence on Matt's computers that he was searching the Internet about sleeping pill poisoning.
Matt says that he has no idea where the crushed pills came from and that he searched the Internet because he was trying to protect his wife who he says was increasingly dependent on sleeping pills.
"I did research to see can you overdose, is that even a possibility that I need to worry about, my wife overdosing on sleeping pills," Matt said.
And Matt asked that if Kari's counselor really believed he would hurt Kari, why didn't she do more to protect her?
"She [Kari] never looked me in the face and said I think you might hurt me," Matt said.
In his interview with "20/20," Matt seemed to contradict himself when discussing who found the suicide note.
On the phone with the 911 operator, he said he found the suicide note, but during his interview, he said a police officer found it first and gave it to him.
And there are other troubling details about what Matt told police and "20/20" about the events leading up to that night.
"It's 11 o'clock. She goes, 'well, go get this movie for me and gas up cause we have a busy tomorrow,'" Matt said.
Matt's 45-minute trip was confirmed by surveillance cameras and receipts. When he got home at midnight, he found his wife dead and nude behind a locked bedroom door.
Tom Bevel is a former Oklahoma City homicide detective hired by Kari's family as a crime scene analyst. Bevel says paramedics told him that lividity, a reddish rash that normally forms an hour to three hours after death, was just forming on Kari's body when they arrived. He says this indicates that Kari must have died long before Matt left the house for a movie.