A story of secret lives involves a fire chief who spent his days battling blazes on the front line. Police say he was also battling a fire building inside of him. Then one day, he snapped.

Brunette stunner Sarah Douglas's wholesome good looks lit the flames of desire in men everywhere, including in the eyes of Orville Fleming, a decorated fire chief almost three decades older than her.

Orville Fleming was a family man, married for 30 years, with a naughty habit. Cops say he cruised a website advertising female escorts, fetishes and other X-rated services. That's allegedly how the fire chief hooked up with Sarah Douglas, and they became a couple.

Fleming filed for divorce and moved the 24-year-old Douglas into his Sacramento, California home. Sarah Douglas quickly upgraded from escort to fiancée.

"She was involved with the website, she had a profile on the website and was an escort on the website," said Sacramento County Sheriff's Sgt. Lisa Bowman. "In her past, we know that's how she met him."

The couple had a volatile and toxic relationship, breaking up, then making up, with heated fights that often turned ugly.

Sarah Douglas's friends and family were terrified that if she stayed with Fleming, she'd be in grave danger.

"The minute that my sister, which is Sarah's mother, met him, she said 'Something's not right with him, and I think he may kill my daughter,'" said Douglas's aunt Trina Werly.

Then, on a Saturday night, Douglas came home after partying with her mom and sister at a nearby casino. Fleming was waiting at home. The conflicted couple has a fight to end all fights.

"She tried to leave him. On Monday she packed her stuff, and then they, I guess there was some type of altercation," said Werly.

Sarah Douglas makes a tearful phone call to her sister when the line suddenly goes dead.

When cops get to the house, they follow a sinister trail: a bloody knife, blood spots on the tiles and smeared on the wall -- and in a dimly lit bedroom, a grisly discovery. They find Douglas's lifeless body on the floor. She had been stabbed multiple times and strangled with bedsheets. But Orville Fleming was nowhere to be found.

"This person is responsible, we believe, for the murder of another individual, and it's not just a murder, it was a very brutal and violent attack," said Sgt. Bowman.

An all-points bulletin goes out for the capture and arrest of Orville Fleming. But finding the 24-year veteran of the fire department would be tricky. Fleming had survivalist skills and knowledge of the Sierra Nevada region close to where he lived.

"I understand he has a lot of guns, he's a fire chief," said Trina Werly.

And cops say Fleming held the keys to the fire station, lookout towers and storage sheds stocked with food and water -- all the ingredients to help a fugitive survive.

More than 11 hours after detectives zeroed-in on Fleming as a suspect, the CAL FIRE truck he drives was spotted just two miles away from his house. Investigators tell Crime Watch Daily Sacramento affiliate KTXL that blood was splattered all around the truck. Where could Fleming be? Police were baffled.

"We really had no good leads as to what condition we would find him in, or where," said Sacramento County Sheriff's Homicide Detective Brian Meux.

Did he flee to Mexico? Did he alter his appearance and go underground?

After a 16-day manhunt, hunger and heat flushed out the fire chief. Fleming, hiding in plain sight, had been hunkered down for days in shrubs in Elk Grove, California, not far from his Sacramento home.

"He, being Mr. Fleming, said he wasn't looking to make a scene. He realized that basically the jig was up at that point," said Det. Meux.

All the high-tech tools used to try to pin him down were no match for the eyes of the deputy who watched Fleming get on a bus, headed out for food.

"We are better at hunting fugitives than he is at being a fugitive," said Meux.

Sheriff's deputies arrest Orville Fleming, book him and begin a jailhouse interrogation, wherein Fleming details the horrific events of that tragic night, which he says all started with a heated argument.

"I went in there and I held her down on the bed, I was sitting on her body and I held her down on the bed, and I was trying to reason with her and talk with her. But at some point in time all that came out of her mouth was 'You are just a piece of [----], you're just a piece of [----], you are a loser, you're a loser, you're just a piece of [----].'"

Fleming alleges that Sarah Douglas was fuming when she found out her husband-to-be bought her a cheap engagement ring with a fake diamond from Walmart.

"Boy, she loved it at the time, but when she found out it was fake, it became an issue for her."

And Fleming finally snapped.

"And then at some point in time, I got up, I went into the kitchen and I got that big knife, and I went back in there and I threatened her with it. She told me I don't have the balls, she told me that I was a piece of [----], and I remember stabbing her the first time. Because I've been laying in the bushes for a long time thinking about this.

"I don't remember anything in the middle of that, until the very end. I was sitting on her waist, she was face down between the wall and the bed, and it was all done. It was all done. I stabbed her. I killed her."

After his stunning admission, Orville Fleming takes us on a dark journey, laying out his steps just moments after committing the heinous crime.

"I took her pulse. I could see that she wasn't breathing or had no pulse. At that point in time, I didn't really know what I was going to do. I mean I really didn't. No one plans for this. I guess some people plan for this. I drove for a moment and then I'm like thinking 'What the hell am I going to do?'"

What he tried to do was kill himself three times that night, by attempting to slit his writs, by filling his garage with carbon monoxide, and by getting hit by a train.

"I was going to go lay on the train tracks. That's what I was going to do."

That astonishing jailhouse confession sealed Fleming's fate. A jury found the former battalion chief guilty of second-degree murder. Orville Fleming was sentenced to 16 years to life in prison after his fiery temper led to the murder of his soon-to-be wife.

Sixteen firefighters were placed on paid administrative leave during the investigation that followed Fleming's arrest.

In the end, investigators concluded the rumors of a firefighter sex tape were unfounded.