Denise sent her husband and his friend on a hunting trip. She knew only one would return.

For 18 years Mike Williams’ body lay buried in the woods near his childhood home. The 31-year-old father of one had been wrapped in tarpaulin, and dropped into a hand-dug hole in the dry bed of Carr Lake, Florida. Untouched, undiscovered.

It wasn’t what his wife, Denise, had planned.

But no matter, because for 18 years authorities still viewed Mike’s death on December 16, 2000, in the way she had hoped they would: nothing more than a tragic boating accident.

“I ended up shooting him.”

Denise wanted out of her marriage. What she didn’t want was the public humiliation of divorce, or the possibility of sharing custody of her infant daughter.

According to court proceedings reported by local paper, The Talahasse Democrat, Denise plotted with her husband’s best friend Brian Winchester, with whom she’d been having a three-year affair, to take him on a pre-dawn duck hunting trip at Florida’s Lake Seminole and push him overboard. He’d likely drown in his heavy hunting outfit, she assumed, and it would seem like an accident.

Then she and Brian could be together, then she could collect the US$1.75 million (AU$2.43 million) worth of life insurance policies Mike had taken out six months earlier.

But Mike didn’t drown that day.

After being shoved out of the boat by Brian, the real estate appraiser struggled out of his wading pants and back to the surface. Brian panicked.

“I didn’t know how to get out of that situation," he told a Florida court according to The Democrat, "so I loaded my gun and made one or two circles around and I got closer to him and he was in the water and as I passed by I shot him... in the head.”

Brian then dragged Mike's body back into the boat, drove back to shore and placed it in the boot of his car, before refloating Mike's boat out onto the water. He then drove to a hardware store, purchased a shovel, tarp and weights to keep the body submerged, and headed for Carr Lake.

That evening, Brian joined the search for his friend. The friend whose blood he'd hosed from his car just hours earlier.

The alligator theory.

Without a body, authorities ruled Mike's death an accident. It was speculated that his remains had likely been eaten by alligators.

Some had suspicions; Mike's mother, Cheryl, chief among them. Unlike Denise, she publicly questioned the police findings, was vocal in local media and pointed to the opinions of experts that alligators do not feed in winter. According to CBS, she wrote 27 pages of notes and evidence, and wrote to the governor of Florida every day for nine years.

Still, Denise got what she wanted. The money, the new life with Brian. They even married in 2005, but as the Associated Press reported, the relationship soured and they divorced in 2016. That same year, Brian held his ex-wife at gunpoint, a crime that would land him in prison for 20 years after he struck a deal with prosecutors.

The details of that agreement have not been disclosed, but the day after Brian's sentencing authorities announced the discovery of Mike Williams' remains at Carr Lake.

On May 8, 2018, Denise Williams was arrested and charged.

During the trial, Brian served as a key witness for the prosecution, having been granted immunity in exchange for his testimony.

Though Denise maintained her innocence, on December 15 - one day shy of 18 years since her husband's murder - a jury convicted her of three counts, including first-degree murder and conspiracy to commit murder.

Footage from the courtroom shows Mike's mother shaking, holding back tears moments after the verdict. According to USA Today, she uttered five words to the district attorney: "We got justice for Michael."