The sedative slipped into the prisoner's veins almost unnoticed.

Just before the lethal injection, the murderer turned to Michael Ward, who stood watching just a few yards away, and breathed: "Adios amigo. I'll see y'all on the other side."

With that, the life of Aaron Christopher Foust, which had started 26 years earlier, came to an end.

That searingly hot day a few miles out of Houston, Texas, also marked the end of a nightmare into which Michael and his family had been plunged nearly two years before.

It began early in 1997 when Michael, who lives in Saltdean, Brighton, received a worried phone call from his mother, waiting at Manchester Airport.

His brother, David, a hospital vice-president, was due to fly to England to see his family. But his plane had touched down and there was no sign of him.

Michael, 40, said: "We found out later he had left work full of the joys of spring because he was planning on coming home for a two-week holiday.

"When I phoned the hospital and explained who I was, they agreed to send around security to his house. They saw his BMW car was gone but the home appeared to be secure."

Michael, however, knew all was not well. He said: "When you're raised in a close family environment you can tell when something is wrong. It's like a sixth sense."

David Ward had grown up as the eldest son of a closely-knit family in Lancashire. In the mid-Seventies he emigrated to Fort Worth, Texas.

Afiercely hard worker, his career took off and by 1995 he was a hospital vice president who had raised millions of dollars for Aids sufferers.

Worried about his brother, Michael eventually convinced John Peter Smith Hospital, Forth Worth, to contact police who broke into the house later that night.

What they discovered not only destroyed a family but shocked America.

David Ward's body was lying bound and gagged in his bedroom. Around him, his home had been ransacked and daubed with gangland graffiti. A post-mortem later revealed he had been tortured for several hours.

Michael said: "When I picked up the phone and they asked if it was me, they didn't need to say anything else. I could sense something was wrong.

"Perhaps the hardest thing I have ever had to do in my life was explain to my parents what had happened. I drove up to Blackburn to meet them that afternoon."

Less than 12 hours from the time of his mother's airport phone call, Michael was on a plane heading for Texas.

He said: "On the flight, I didn't feel anything, I was numb. I was still trying to reconcile in my own mind the events that had taken place.

"It's totally foreign to anything you've ever experienced before. It wasn't a natural death for which you could have prepared."

After touching down, Michael had to clean up the wreckage in his brother's house, arrange his funeral and wind up his affairs.

In the midst of all this, a huge manhunt had started for the killers. David Ward had been a well-known and highly respected figure and his murder was headline news across the country.

Three days after the death, a restaurant manager told police about two men who had ordered beers and a meal.

When he asked one for ID, he noticed it didn't match the name on the credit card - David John Ward.

Aaron Foust and his accomplice were caught hours later, a few miles from a burned-out BMW.

Foust had embarked on a life of crime at an early age and had spent much of his life in prison, where he had earned the nickname Conan for his muscular build.

Not only was he a crack cocaine addict, he was also a nihilistic psychopath who dreamed of killing a police officer.

He had been out of prison for just two days - serving a sentence for GBH for beating up a woman - when he killed David Ward.

Michael said: "The authorities released David's body within days and I brought him back to Blackburn, it was my mother's wish that I flew back with him."

Michael, who works for the Midland Bank group in Worthing, tried to pick up the pieces of his life with the help of his wife, Susan, 37, and their three children, Jennifer, 12, Rebekka, 11, and Alex, eight.

But the horrific way in which David's life had ended meant many trips to America to assist the district attorney, attend memorial services arranged by friends, and wind up his brother's estate.

In April last year, Foust's three-week trial for first degree murder began in Tarrant County, Forth Worth, and Michael made sure he was there to see the whole thing through.

It was when he was called as a witness that he first came face to face with the man who had murdered his brother.

He said: "Foust was sitting a few metres away from me and the only way I was able to get through it was by adopting a business-like manner and keeping the emotion out of it.

"Then, just as all the way through the trial, Foust seemed to be finding something amusing - he was smirking, rocking back in his chair and blowing kisses at the jury.

"But he made eye contact with me and knew I was there, and who I was."

During the trial, the jury heard how David Ward had devoted his life to helping others. After his murder, his mother received hundreds of letters from the patients whose lives he had touched.

The jury took five hours to convict Foust - and his reaction was to laugh.

Four days later, he was given the death sentence and he waived his rights to appeal.

While on Death Row, he told other inmates why he had murdered the 43-year-old bachelor whose future was so bright.

He said: "It was his attitude. He had a real arrogant, snobby English kind of attitude.

"Here's a guy who's got a good job and education. It takes a good deal of determination to put a man in a chokehold and choke the life out of him."

Foust had tasted the harsh reality of prison life before and was in no mood to sit in his cell for years as the appeals dragged on.

He said: "Now I am ready to die. I don't want to spend the rest of my life without a woman. I'm guilty."

Last week Michael Ward stepped from an aeroplane at Houston Airport in an attempt to exorcise the demon which Foust had become to his family.

At 6.05pm local time on Wednesday, he walked across the courtyard of The Walls Prison, avoiding the anti-death penalty campaigners and TV cameras.

Afew minutes later he was in a tiny room where Foust, dressed in white prison regulation uniform, was strapped to a bed, a tube sticking from either arm.

Although bars and a glass screen separated them, Foust, already heavily sedated, turned to look at his victim's brother.

Michael said: "He leaned his head to one side and did his usual smirk - he knew I was there. He was asked if he had any final statement. He said 'Adios Amigo, see y'all on the other side'."

At 6.16pm a massive dose of drugs was pumped into Foust's arms. Six minutes later he was pronounced dead.

Michael said: "Right up until the end my fear was he would say he wanted to appeal.

"It was all very clean, all very humane and I was actually disappointed by how quick it all was.

"I know a lot of people reading this article will be horrified at what I'm saying.