Woman convicted in 2005 murder of her husband speaks from prison

Former Texas veterinarian and mother of two Wendi Mae Davidson is currently serving 25 years in prison for murdering her husband in 2005. Now she said she is ready to tell her side of the story.

"I did not kill him," Davidson told "20/20" in 2021, in her first network interview from prison. "I want my side of the story, what happened. I want people to know what did and didn't happen."

In October 2006, Davidson pleaded no contest to first-degree murder and two counts of tampering with evidence. She was sentenced to 25 years in prison.

But Davidson has continued to adamantly maintain her innocence.

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"I did what I did, I think it was horrible, I think that I made a bad choice, there were better choices to be made. But I still didn't kill him," Davidson said. "What I did was horrible, there's no excuse. I mean I might have had crazy reasons in my head, but there's no excuse."

In January 2005, Davidson reported her husband, Air Force Staff Sgt. Michael Severance, missing. Two months later, Severance's body was found in a pond on a remote ranch about 20 miles outside of San Angelo, Texas, where the couple was living at the time.

Severance's toxicology report revealed that he had been poisoned with animal tranquilizers and then stabbed 41 times posthumously.

Davidson initially told police that the last time she saw her husband was the day before he went missing.

"He was all concerned about -- he didn't want to be deployed, because he was afraid that something bad was going to happen," Davidson told police in 2005. "And he kept saying like, 'Those guys that go over to Canada, it would be so easy just to go to Canada.'"

At the time of his disappearance, Severance had already deployed five times to the Middle East and was preparing for his sixth tour. The couple had given birth to their first child. Davidson had a son from a previous relationship.

Davidson claimed that the pressure of family and his work was getting to him, including driving three hours round trip to Dyess Air Force Base in Abilene, Texas.

"I was busy, I was in the middle of trying to run this clinic I had just opened, taking care of two little babies. The only thing that I noticed that changed with Mike was he was having a very hard time driving back and forth to Abilene every day. I did notice that every afternoon he was drinking, but then I noticed he was using caffeine pills," Davidson told "20/20." "At the time I didn't realize there was an issue but looking back you know, like hindsight's 20/20 and everything, so looking back obviously there was a problem, that's not normal."

Despite what Davidson said, there was never any evidence to suggest that her husband had a problem with drugs or alcohol.

The San Angelo Police Department, the Texas Rangers and the Air Force Office of Special Investigations (OSI) began investigating Severance's disappearance. However, at the time he went missing, Severance was on leave and an official OSI inquiry could not begin until after he was expected to be back on base. When Severance didn't show up for work, he became AWOL, and the OSI was able to take the lead in a deserter investigation.

A break came in the case in February 2005.

Since the OSI is an arm of the U.S. military, they operate under different constraints than local police and were able to get permission and approval to place a tracking device in Davidson's car. Their reasoning was that if Davidson was claiming Severance may be a deserter, then there would be a possibility she was helping him hide out.

During surveillance, they saw that she had been visiting a remote ranch called Four Sevens Ranch, about 20 miles outside of San Angelo.

OSI and the San Angelo Police Department had also searched the family's home and Davidson's veterinary clinic. They seized her work computer's hard drive and sent it to a lab for analysis.

A few weeks later, the results from the hard drive revealed suspicious searches on the computer, including "decomposition of a body in water."

When the police confronted Davidson with the information, she said she had researched it because during that time volunteer searchers were searching for Severance.

Following the police interview, Davidson called her brother Marshall Davidson, who was a game warden at the time, and told him that she had found Severance dead in the living room and that she dumped his body in a pond on the Four Sevens Ranch, but she swore she hadn't killed him.

"He said, 'Wendi ... I'm a cop, you can't be telling me this,'" Davidson said. "My parents drove up, and me and my brother were telling them everything that happened, which was that I had found him dead and dumped his body in the pond."

Davidson said that her brother said he'd call an attorney, but instead he called investigators and told them what Davidson had told him.

Davidson said that she moved Severance's body to the pond, stabbed the body and weighed it down with cinderblocks.

"I had to take these weights, and I'm trying to tie them onto this body, and of course it's the middle of the night, you know, can't hardly see," said Davidson, who said she stabbed the body because she was afraid it would float to the surface. "I knew air made bodies float, so I decided to make holes in the body, vent holes, like, so that air could escape."

After Severance's body was discovered, Davidson was arrested and taken into custody and charged with first-degree murder and two counts of tampering with evidence.

After Davidson was released from jail on bond, a toxicology report revealed that Severance had been poisoned by animal tranquilizers that Davidson would have had access to in her clinic.

After Davidson was charged, her defense team quickly filed a motion to suppress the evidence gained from the tracking device in her car -- claiming it was illegally obtained -- since, by law, officers need to get a court order to allow them to attach a tracker to a person's vehicle.

Prosecutors argued that since officers thought Severance was AWOL at the time, OSI gained the necessary permissions and approval to utilize tracking devices. The judge ruled in favor of the prosecution, saying the tracker was legal and the evidence gained by the tracker was admissible.

If found guilty in trial, Davidson faced nine to 99 years in prison. After the ruling on the tracker, Davidson took a plea deal and pleaded no contest to her husband's murder. She was sentenced to 25 years in prison in 2006.

Davidson said she does not think she is a "victim."

"I think my husband was a victim, I think my children were victims," she said. "I think Mike's family are victims."

In 2019, Davidson was denied parole and is scheduled to be released from Gatesville Correctional Facility in 2031. She said she has not seen her kids since they were two and five-years-old.