What led a Cajun millionaire to brutally stab his British wife?

What could have happened to a Cajun millionaire-turned-English gentleman to lead him to murder?

Produced by Allen Alter

[This story was originally broadcast on Nov. 26, 2011. It was updated on June 19, 2012]

Writing letters is the way H., as Harold Landry is known to his friends, can communicate with most of them, including Helen Knifton.

"This is a letter from H. in prison sent on the eighth of September 2010," she told "48 Hours Mystery" before reading the letter: "I am truly settled in-keep so busy doing so many things."

H. left the majesty of his country house for Her Majesty's prison system. He had confessed. He stabbed his wife, Lucy, to death.

"All I ever did was love her. Still do."

His correspondence from behind bars reads like love letters to the woman he killed.

"All I ever did was give her everything she asked for. For 10 years, she never ever worried about anything."

Knifton is used to communicating with H. in writing from her home in the English countryside. They met online before H. met Lucy. The virtual world made it possible for her to befriend someone from a very different world.

"His handle was Cajun H," she said.

"H. grew up in a small town on the bayou called Berwick, La., with a dozen brothers and sisters," Pat Fanning, a lawyer and H.'s friend in New Orleans, explained. "He managed to pull himself from that meager existence that he lived there and made millions in the oil field."

Landry made his fortune designing cranes for offshore oil platforms and was a well-known employer around Covington, La.

"When it came to business, he was a very tough guy, but he was never that way with his family," according to Fanning. "He had been divorced a couple of times, but he took care of his kids and made sure they were educated and had everything they needed."

By 1999, he was healthy, wealthy and lonely. And that's when he went looking for love in that thoroughly modern way -- online.

"Call me old fashioned," Fanning told correspondent Richard Schlesinger, "but I don't find that a particularly romantic way to find a bride."

But H. Landry found the woman for him. Lucy Davies, whose online name was "Misery," was a music student who lived in England with her 4-year-old son.

H. was 53; Lucy was 28.

Wanda and Ernie Richardson are two of H.'s closest friends.

"At first I was a little bit negative about it," said Ernie.

"What are you doing? Wanda said. "Look at the age difference!"

"But I know H. loves to be around lively, beautiful things and Lucy was certainly that," added Ernie.

"There was something about her that was kind of like, what you see is what you get," Wanda said. "I liked her a lot."

And the Richardson's enjoyed seeing H. so happy with Lucy.

Wanda said, "He doted on her, oh my, gosh, did he."

"Lucy was being pampered and she was enjoying it," said Ernie.

"She enjoyed beautiful clothes, beautiful jewelry," said Wanda.

And H. was willing to buy whatever Lucy wanted.

"If you want to get the hoochie you got to buy the Gucci and he knows that," said Fanning.

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Some of H.'s friends soon began wondering if Lucy enjoyed the clothes and the jewelry more than she enjoyed H.

"H. at one point showed me a diamond ring that he bought for Lucy that he wanted to give to her as an engagement ring," Fanning said. "Lucy wanted the diamond but she didn't want H as part of the deal. ...He wasn't exactly a hunk a hunk of burning love-looking kind of a guy."

Fanning describes the romance, such as it was, as a little more like a business deal.

"The love affair between H. and Lucy was that Lucy loved H.'s money and H. loved Lucy's appearance," he said.

It may not have been for love or money, but H. and Lucy did get married shortly after Lucy got pregnant. And Harold Landry, Bayou born and bred, tried to become an English country gentleman.

"He'd say, 'Well, let's go get the lift,' and I'd say, 'Why don't you take the elevator, dummy," said Fanning.

"I'd go, 'Come on H., you're from south Louisiana. Quit it," Wanda said with a laugh. "But he just dove right into it."

Landry bought a big house in the country for his new bride and settled into his new life as a retiree and as a new father, when his daughter was born.

"He was a very proud papa, no doubt about it," said Ernie.

"What did he tell you about her?" Schlesinger asked.

"Oh, just everything about her, every minor detail," Wanda replied.

"H. is a happy guy," Fanning said. "H. has got his young girl. He got what he wanted."

But both H. and Lucy might have gotten more than they could handle. There were signs, after a few years, that the marriage had become a volatile mixture of anger and alcohol.

The couple had known each other for 10 years when Lucy finally asked for the divorce.

Asked how Landry was during that period, Wanda Richardson told Schlesinger H. was "in a terrible state."

"The most important thing to him wants to leave him and he didn't understand and he didn't know what to do," added Ernie.

Of course, H. had already been married twice and divorced twice. This time, things would be very different.

British police officer Steve Elcocks was one of the first officials on the scene.

"And I'd certainly never been to anything like it before," he explained. "The paramedics were working on Lucy. ...There was a great deal of blood."

Lucy had been stabbed more than 20 times.

"She had a very, very large gash to her left cheek. She also had a very large butcher's knife that was still in her," the officer said.

Officer Elcocks had his hands full.

"One of the first priorities was to find out if those children were safe," he said.

Police found the children, ages 7 and 14, in the backyard. They did not know their mother lay dying in the front.

H. had fled, leaving the children alone at the bloody crime scene. Police immediately began searching for Landry along dark, deserted country roads.

And that's where Sgt. Ian Booth found him.

"It was just before midnight," Sgt. Booth said. "Slammed on the breaks and I knew it was him straight away."

Sergeant Booth arrested Landry and charged him with murder.

"Mr. Landry was completely compliant," he said. "There's nothing in his demeanor to suggest he'd just done something."

Landry didn't try to deny it. He told police what he had done.

H.'s friends couldn't believe it, but Pat Fanning knew firsthand about the other side of Harold Landry.

But Pat Fanning knew first-hand about the other side of Harold Landry.

"I knew H. as a guy who got crossways with a guy and shot him," he said.