UPDATE February 7, 2019:

A Florida woman convicted of helping mastermind the killing of her husband nearly two decades ago has been sentenced to life in prison, WJXT reports. A circuit judge sentenced Denise Williams on Wednesday, also giving her 30 years for conspiracy.

Williams was convicted last December of first-degree murder and conspiracy to commit murder. Williams conspired with her husband's best friend -- who was also her lover -- to murder her husband on their sixth wedding anniversary in December 2000. Prosecutors argued that she plotted the killing in a scheme to get a $1.75 million life insurance payout.

Brian Winchester, the best friend, testified he had an affair with Williams and shot her husband in December 2000. Winchester helped authorities find Mike Williams' buried body in 2017.

MORE: 'Mastermind' in husband's 2000 killing gets life in prison - WJXT

UPDATE December 14, 2018:

Denise Williams was found guilty Friday night for her role in the murder 18 years ago of her first husband, Mike Williams, Tallahassee.com reports.

After eight hours of deliberation, a Leon County jury convicted the 48-year-old of all three charges against her. She faces life in prison for conspiracy to commit murder, first-degree murder and accessory after the fact for masterminding and concealing a wicked plot to free her from the marriage and collect nearly $2 million in life insurance money.

UPDATE June 1, 2018:

Brian Winchester and Denise Williams are both are behind bars. The 47-year-old Winchester is serving a 20-year prison sentence for kidnapping Denise Williams, 48, in 2016. She’s in jail, arrested May 8 and charged with Mike’s murder, the planning of it and its cover-up, the Tallahassee Democrat reports.

September 30, 2016:

Missing Florida man Mike Williams's wife Denise had him declared dead six months after he went missing, then she remarried. She was arrested in May on suspicion of Williams's murder five months after his body was found.

UPDATE May 8, 2018: Denise Merrell Williams was arrested Tuesday, May 8, 2018, on suspicion of Mike Williams's 2000 death, the The Tallahassee Democrat reports.

Denise Williams, 48, was indicted Tuesday morning by a Leon County grand jury on a charge of first-degree murder. She was led away in handcuffs from her office at Florida State University, where she worked.

UPDATE December 22, 2017: The Florida Department of Law Enforcement announced that Mike Williams' remains had been found and that he'd been murdered, reports WCTV.

Multiple sources tell WCTV the remains were discovered at the dead end of Gardner Road. That's off Meridian Road in Leon County, more than 50 miles from the lake front authorities searched years ago.

Sept. 30, 2016:

This is gator country, a beautiful but treacherous stretch of swamp near Tallahassee, Florida.

The blood runs cold in the powerful reptiles that rule the water in the swamps near Tallahassee, Florida. Is Michael Williams the victim of another kind of cold-blooded killer?

Michael Williams was a man who seemed to have it all: A successful career in real estate, a beautiful wife, a sweet young daughter, and a longtime love for duck hunting. Friends say Mike would grab any chance to hunt, even if he had to sit alone in his boat on Lake Seminole.

The glistening waters of Florida's Lake Seminole, just outside of Tallahassee, had always been a favorite spot for Williams.

On a December morning in 2000, as a whipping cold front was tearing into Tallahassee, Michael grabs his shotgun and heads out to the lake.

Mike promises his adoring wife Denise that he'll be back by noon. After all it's a special day: The loving couple is celebrating their sixth wedding anniversary.

Well past noon, Mike hasn't returned home from his hunting trip. Daylight curls into darkening skies, and Denise becomes frantic. She phones her dad, and friends rendezvous at the lake. Brian Winchester and Denise's father lead the desperate search at dusk for her missing husband.

Florida Fish and Wildlife Officer David Arnette was the first investigator called to the scene. The search was called off for the night, but the next day they get their first break into Mike's mysterious disappearance: They find his boat with some of his equipment in it. But there was no Mike.

Search-and-rescue divers, helicopters and hundreds of hours of law-enforcement officers worked over weeks, then months, scouring the lake looking for Mike.

Florida Fish and Wildlife investigators believed he had been pulled under by the weight of his fisherman's waders and drown in the shallow depths of alligator-infested waters.

Mike's mom Cheryl says there is one big problem: "Alligators do not eat in cold water." It was bitterly cold the day Mike went missing.

"Alligators don't eat people whole. If they do attack, the chew on people, they tear arms and legs off," said Florida Department of Law Enforcement Special Agent Mike DeVaney. "There's always parts found after an alligator attack."

But not a gnawed human bone nor a shred of human flesh has ever surfaced from those muddy waters. Investigators searched for 44 days and never found Mike nor his body.

"Every single person that went missing on that lake had been found, recovered," said DeVaney. "This was extremely unusual."

Adding to the mystery, Florida Department of Law Enforcement Special Agent Mike DeVaney is told alligators become zombie-like: They almost hibernate in cold water and don't really eat in wintertime.

After months of searching for Mike Williams, a strange clue suddenly surfaces.

"All of a sudden a hat appears," said DeVaney. "But why wasn't the hat found during that 10-day time period? Because it was floating on the surface, real close to the area Mike put in his boat. People couldn't quite figure that out."

Investigators turn to Mike's best buddy, Brian Winchester.

"Mike's friend Brian Winchester examined the hat," said DeVaney. "And he told the folks, 'This looks like a hat Mike may have owned.'"

But DeVaney says a DNA test is inconclusive.

"Very suspicious," said DeVaney.

Things get even stranger when a fisherman scoops up a pair of waders, the same kind Mike was wearing when he fell overboard. But there is something mysterious about them too.

"There's no body parts in there. There's no sign where an alligator has tore on the waders whatsoever," said Arnette. "They were completely intact. This was six months after the initial search started and you wonder, How did we miss this all this time? We can't connect the dots there."

A short time later, divers at the scene pull up Michael's hunting jacket. His hunting license is still legible. Even his flashlight is still working after six months in the water.

"The condition of these items were so pristine that there was no way they would have been at the bottom of this lake, which is mossy and algae-coated," said Jennifer Portman, news director of the Tallahassee Democrat newspaper. "They were too new. They were so clearly planted."

Mike's mom Cheryl never gave up hope of finding her beloved son. She took out full-page ads in the newspaper and on billboards asking the public for help. She even took to the streets calling for a criminal investigation. But Cheryl says her pleas fell on deaf ears all the way up to the governor's office.

Friends and family say Mike's wife Denise was devastated. After all, she was only 31, a widow with a young daughter to raise alone. She and Mike had dated since the ninth grade at a private Christian school.

Normally in Florida, you have to wait five years before a missing person can be legally declared dead. But just six months after Denise's husband vanished without a trace, she asked for the state to issue his death certificate.

"I had no idea. I was shocked," said Cheryl, Mike's mother.

And what was the evidence Denise used to convince a judge her husband met his demise at the bottom of the lake? His hunting jacket, hunting license, a working flashlight, and the pristine pair of waders with no alligator holes.

Cheryl's crusade to open up a criminal probe seemed to enrage her daughter-in-law.

"After Mike disappeared she threatened me," said Cheryl. "She said 'If you do anything to get a criminal investigation, you're going to lose access to Anslee,' my granddaughter. I had already lost my husband, I lost Michael, and now she's telling me I am going to lose Anslee. I said 'What if that were Anslee missing? Would you not look for her?' She said 'That's different. I have to go on with my life. I don't ever want to hear Mike's name. I don't ever want see Mike's face.'"

To this day a broken-hearted Cheryl hasn't seen her adorable granddaughter.

In the tragic case of Mike Williams, his family believes greed may be at the root of his death. In the months before Williams went missing, his wife took out a million-dollar life insurance policy on her husband. And making thing even more suspicious was the man who helped her sign the papers.

"I believe he was killed and I believe that his body was taken somewhere else, and I believe that his truck and boat was left over, staged over there," said retired Jackson County Sheriff's investigator Derrick Wester.

"There were two insurance policies, one that was written about six months before he went missing. That was for $1.5 million. We don't know if Mike ever knew that this insurance policy was taken out, though it was filled out as if it was him," said Jennifer Portman.

Retired sheriff's investigator Derrick Wester inherited the case four years after Mike vanished.

"If it hadn't been for his mother, a criminal investigation would have never been opened. It would have been a missing person that was never found," said retired Jackson County Sheriff Derrick Wester.

Mike's widow Denise was the beneficiary of a huge life insurance policy.

Mike's old boss Clay Ketcham was like a father to Mike.

"He said 'What would be your advice?' And I said 'Mike, given your age at life, and given your risky behavior, I would buy all the life insurance I could,'" said Ketcham.

"Brian Winchester sold insurance," said Jennifer Portman. And Brian Winchester was close pals with Mike and Denise.

"Brian Winchester had sold him a life insurance policy," said Derrick Wester.

"The suspicion is that his wife went ahead and did this with Brian, and Mike was unaware of it," said Portman.

Investigators also found curious that Mike's shotgun found in the empty boat is not for duck hunting. And Ketcham says Mike kept all his guns in the office for safety. To enter after-hours, a personal password is needed to turn off the alarm.

"I can't tell you Mike Williams came in here -- I can tell you that the door opened when Mike Williams' code was inserted," said Ketcham.

Ketcham regrets never telling investigators at the time that Mike had a terrible secret weighing on shoulders: the seemingly perfect marriage to his high school sweetheart Denise was on the rocks.

But there was another theory that surfaced about what could have happened to Mike: Did he fake his own death?

The ink was barely dry on Mike's death certificate when his mom found out that her daughter-in-law was having a torrid affair with her son's best friend, Brian Winchester.

"We were told on numerous occasions that Brian and Denise were having an affair before he went missing," said Wester.

In fact Brian Winchester actually got a divorce and married his best friend's wife.

Many in Tallahassee believe Mike's ex-wife and her new husband, who used to be Mike's best friend, know more than they're saying. So we decided to pay them a little visit.

"A question came up when his spouse started to inquire about obtaining the insurance monies during the search," said DeVaney.

Mike's mother and brother say his widow Denise has been living on easy street since she collected at least $1.5 million in death benefits.

Initially, investigators looked at the case as a tragic boating accident: Mike possibly drowned and his corpse was eaten by alligators. But there are a bunch of clues from the scene that don't add up.

  • His boat was found with a full tank of gas like it had never been used that day.

  • The shotgun, Mike's brother says, was not the one Mike used to hunt ducks.

  • Mike's jacket, hat, waders, even his hunting license were not found until months after Mike disappeared, and despite all that time in the water, they were all in pristine condition.

  • And Mike's body remained missing.

"There's no physical evidence so at every turn, it's really tough. No arrests are made, no suspects are named, because all you can get is this story that seems suspicious, but it doesn't kind of cross that line where you can actually take any action with it," said Portman.

Investigators launched an insurance probe but couldn't prove anything underhanded.

Brian Winchester has never been charged or named as a suspect in Mike Williams' disappearance.

Crime Watch Daily wanted to get his side of the story, so we went to Brian's insurance office, but he couldn't be reached.

Shortly after my visit, we find out there is big trouble in his marriage with Denise. Winchester is arrested for allegedly kidnapping Denise and holding her at gunpoint in her car. He was reportedly distraught over their impending divorce. He allegedly told her he's going to kill himself. Denise and her now teenage daughter beg the judge to keep Winchester behind bars.

Brian Winchester has pleaded not guilty to the charges of kidnapping, aggravated assault with a deadly weapon and armed burglary.

Denise has never been charged in Mike's disappearance.

Cheryl vows to fight for justice for Mike. As for Brian Winchester, he remains in jail after pleading not guilty.