When Dan and Avis Winters discovered that their daughter had succumbed to suicide, they simply couldn’t believe it. Their daughter was not suicidal and had gone to therapy for depression and anxiety due to marital problems as well. Therefore, they hired a retired FBI agent to follow the person they believe was responsible and also filed a civil suit against him. In this article, we discuss the person who was the prime suspect in the homicide of Susan Winters, whose story has been featured on Investigation Discovery’s ‘A Deadly Dose.’
Who is Gregory Brent Dennis?
Dr. Gregory Brent Dennis was a licensed psychologist who had been married to a lawyer and part-time judge, Susan Winters. The couple resided in Henderson, Nevada, and had two teenage daughters well. He had also played football while attending the University of Tulsa. He operated a clinic in Boulder City.
On January 3, 2015, Susan was found unresponsive by her husband who then called 911— “My wife is unconscious, she’s warm. I got to give her mouth to mouth. I’ve got to do something.” Although she was taken to St. Rose Siena, unfortunately, she did not make it. Dennis told investigators that his wife was depressed and that their marriage was an emotionally distressing one. The coroner’s office ruled her death a suicide due to ingesting antifreeze and oxycodone, and the case was closed.
But the Winters family was not convinced that this was the truth. They felt that Susan loved her daughters too much to do this. Dan claimed that even if Susan did want to kill herself, she would not have done so in a manner that took 24 hours to take effect. Also, a suicide note was missing. Her father was adamant: “There’s no way in hell that she would have taken her own life. No way in hell.” The parents then filed a civil suit against Dennis to find out the truth.
For two years, Susan’s death had been accredited to suicide. But after new information came to light, the Clark County Coroner’s office changed her cause of death to undetermined. It turned out that there was little evidence to support the husband’s claims. The Winters’ family attorney, Anthony Sgro, said, “No anti-freeze in the room. No glass with any remnants of anti-freeze liquid in the room, no prescription bottle for oxycodone, no suicide note. This whole notion that she was somehow able to ambulate to the garage, only to ingest sufficient anti-freeze to kill herself, put the anti-freeze down, neatly put the cap back on it, then go back to bed, it’s preposterous.”
Susan’s husband received a Marcum letter from the Clark County district attorney’s office that informed him of the investigation. The court documents alleged that the motive for the homicide was a financial one. You see, Dennis was allegedly battling a cocaine addiction that had drained him financially. Furthermore, he received a million-dollar life insurance policy after Susan’s death and an additional $650,000 inheritance from her family’s Sonic franchises. Susan’s family members also stated that the husband had asked about the money the very next day after her passing. Furthermore, a cheque worth $180,000 was cashed by Dennis from his deceased wife’s bank account.
Apart from this, Dennis claimed that his wife had searched about the lethal aspect of antifreeze on their family computer, and he found bottles of the substance in his garage as well. But the reports alleged that it was in fact Dennis, and not his wife, who conducted the search. Plus, if Susan had already ingested the oxycodone, then how could she have walked to the garage for the antifreeze? Next arose the question of how Susan, who did not have a prescription for the drug, obtained oxycodone in the first place.
The data from the computer and phone records also painted another story. Dennis had accepted that he had undergone treatment for drug addiction in the past, and he used to buy them from a dealer named Jeffrey Paul Crosby. The latter was a convicted drug felon. Moreover, a few days before her death, Susan had texted Crosby and had also confronted her husband about his alleged drug usage, threatening to reveal it to the authorities. Dennis, who claimed to be in his bed when his wife died, was actually placed in the vicinity of the Orleans Hotel. He had texted Crosby between 2:57 a.m. and 3:14 a.m. that night. The two spoke again around 5:32 in the morning. It was around this time that the aforementioned computer search occurred, and an hour later, Dennis made the 911 call.
Anthony Sgro said, “I mean, you got to really compare, I was home that night. I fell asleep and then I woke up, that’s the story, to the actual facts that developed. He’s on the cell phone all night, speaking to people all night. He left the residence. He was on the Internet doing searches. From what the cell phone records, his departure in the middle of the night, the Internet searches bear out, he didn’t sleep at all that night. Quite the opposite of what he told the police.”
Where is Gregory Brent Dennis Today?
Dennis was suspended by the state’s Board of Psychological Examiners from practicing, but by July 2017, he was allowed to reopen his clinic. Although he maintained his innocence, a grand jury convicted him on one charge of open murder with a deadly weapon in October 2017. According to an article on the Las Vegas Review-Journal dated December 2019, he was out on a bail of $250,000 that had been posted days after he was arrested from a traffic sign in front of his house. His trial was supposed to commence in February of the next year, but it was further pushed back to September due to an issue with discovery and a scheduling conflict.
Read More: How Did Susan Winters Die?