NBC Dateline: Why did Susan Winters' husband Gregory Brent Dennis kill her and where is he now?

In 2017, a Henderson psychologist, Gregory Brent Dennis, was arrested for the murder of his wife, Susan Winters, who died of antifreeze poisoning about two years prior to the arrest. The case, which was initially ruled a suicide, later took an unexpected turn when the cause of death was changed to undetermined, changing the previous status, which was suicide.

It was alleged that Dennis poisoned his wife to claim over $1 million in life insurance claims and inheritance money to support his drug problem. Earlier this year in May, he was sentenced to prison after entering an Alford plea and is currently serving his mandatory term of three to ten years in prison for voluntary manslaughter in connection with the 2015 death of his wife.

NBC Dateline is scheduled to revisit Susan Winters' case and husband, Gregory Brent Dennis' alleged involvement in the murder, in an upcoming episode. The episode, titled A Cool Desert Morning, airs on Friday, October 7, 2022, at 9 pm ET.

Read more to learn about the antifreeze poisoning case.

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Gregory Brent Dennis claimed over $1 million in insurance claims after Susan Winters' death

During the initial stages of Susan Winters' 2015 death, it was concluded that the mother-of-two committed suicide by taking a deadly quantity of prescription opioids and antifreeze together. This information was disclosed to authorities by husband Brent Dennis back then.

However, investigators eventually discovered that Dennis misled them about his wife's death and had a possible financial reason behind it.

It was further revealed that the couple had previously separated for a few months in 2013 and were going through a tumultuous patch at the time of Winters' death.

Reports state that Dennis had a drug problem and was draining their finances at the time. Susan even confronted the husband about his alleged substance abuse and threatened to report him to cops and the state licensing board.

Brent Dennis, who claimed he found his wife unresponsive early on January 3, 2015, reportedly claimed over $2 million in financial claims, half of which were to be acquired from his wife's life insurance policies. Moreover, incriminating internet searches, such as the duration of killing an individual using antifreeze, which contains ethylene glycol, were also found.

According to prosecutor Marc DiGiacomo, Dennis didn't contact 911 right away and instead waited to make an emergency call after his wife took opioids and also gave the hospital a do-not-resuscitate order.

He also transferred $180,000 into his bank account shortly after the death and even informed a friend about the money, claiming that he was aware that her parents were going to seize all of her holdings.

Prosecutor DiGiacomo reportedly stated:

"He [Brent Dennis] knew that when she died that her parents would freeze that account. The problem for Mr. Dennis is, he knew some nine hours before her death that she was going to be dead."

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Husband Brent Dennis entered an Alford plea for Susan Winters' murder

In January 2015, Susan Winters' body was discovered at the couple's Henderson house. Her death was initially classified as suicide, but Dennis was detained in February 2017 on suspicion of murder. The victim's cause of death was reclassified as "undetermined" around two months after Dennis' arrest.

In January 2022, Dennis entered an Alford plea, admitting that the prosecution had evidence to support his guilt but avoiding a guilty plea. A few months ago in May, he was given a maximum ten-year prison term for voluntary manslaughter in his wife's death.

DiGiacomo further stated:

"While the defendant did not make a verbal admission of guilt, he agreed to receive a 10-year prison sentence for killing his wife. A sentence of that type for a 60-year-old man is clearly justice for Susan."

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Dateline's upcoming episode reporting on Susan Winters' 2015 death from anti-freeze poisoning airs on NBC this Friday, October 7, 2022.