On Friday, 7 August 1998, FBI agent Steve Gaudin was on holiday on the New Jersey coast when he was called and told to return immediately to his New York office.
BBC Two's Age of Terror: War on the West preview
Still in his Bermuda shorts and flip-flops he drove back to New York city.
The radio in his car was broken so he had no idea that two bombs had just destroyed two US embassies in East Africa in an apparently co-ordinated attack.
Within hours he was on his way to the Kenyan capital Nairobi with an FBI unit, assigned to provide personal security for the leader of the team, Pat D'Amuro.
By Sunday they were standing at the site where over 200 people had died and a massive rescue operation was still underway.
Two days later, one of many anonymous phone calls to the makeshift FBI headquarters indicated that a man had booked into a hotel in a suburb of the city and was acting suspiciously.
Pat D'Amuro needed to send someone to check out the story.
He turned to his security officer Steve Gaudin and said: "I've got hundreds of leads here, I've got everybody going in thousands of directions. Let's face it, I know you're here to help protect me... but you're not going to be able to protect me here. I want you to check out this lead."
Gaudin, armed with just six years service in the FBI and no previous experience in international terrorism, set out on what would turn out to be one of the most extraordinary assignments of his career.
Early the next morning, Gaudin arrived in a suburb called Eastleigh, accompanied by members of the Kenyan police force and two colleagues from the US.
Eastleigh is known locally as Somalitown because so many Somali immigrants live there.
The Kenyan police advised Gaudin that someone looking so obviously North American could be in danger in that part of town, so he travelled out of sight in the back of the van.
In Eastleigh, they soon found the man who had been acting strangely. His hands were injured and he had a number of stitches on a wound to his forehead.
Steve Gaudin explains what happened when he first met an al-Qaeda suspect
Back at the police station in Nairobi, Gaudin began questioning him.
He said his name was Saleh and that he had been injured in the bombing. He also said that his friend - the only other person he knew in Nairobi - had been killed in the blast.
Saleh was treated in hospital and had been recovering in a small hotel in Eastleigh for the last few days.
But Gaudin was curious about his appearance.
What had he done with his old clothes? The clothes he had been wearing on the day of the bombing.
The clothes he was wearing were very clean for someone who had injuries on his forehead, both hands, and even in the centre of his back. He had a huge amount of stitches, yet there were no holes, no tears and no blood.
Saleh claimed he was wearing the same clothes he had been wearing on the day of the bombing, but Gaudin felt sure he was lying.
Unravelling the truth
As the questioning continued, Gaudin also began to get the sense that Saleh had been trained in counter-interrogation techniques.
When he put this to him, Saleh did not seem surprised.
Describing the moment an al-Qaeda suspect in the Nairobi bombings confessed
He accused Saleh of telling him an "illogical lie", and instead of looking confused, Saleh immediately asked: "Where was I illogical?"
Gaudin interviewed Saleh for 10 days.
During that time his colleagues were investigating other leads and producing evidence including incriminating telephone records and forensic evidence of explosives at a house which Saleh had contacted by phone.
Everything pointed to Saleh's involvement and Gaudin finally presented all the evidence to him.
Then, suddenly, Saleh changed tactics.
He told Gaudin the whole story.
What happened after an al-Qaeda suspect confessed to the 1998 Nairobi bombing
His real name was Mohamed al-Owhali. He had not only been involved in the plot, he had in fact been personally selected by Osama Bin Laden to be one of the suicide bombers.
But due to some last-minute errors and confusion, he had decided not to die with his fellow bomber.
At the last moment, he had run away.
Three weeks after the bombing, Steve Gaudin accompanied al-Owhali back to the US to face trial.
In May 2001, four months before 9/11, he was found guilty of involvement in the bombing and was later sentenced to life imprisonment.
Steve Gaudin described this extraordinary case as a "life-changing experience" and on his return to the US, did not go back to domestic criminal work.
Looking back, he remarks: "The thing that really stuck out in my mind was... this is going to continue.
"If you work a drug case, you arrest the drug dealers and you move on. This, in my mind, did not have an ending. And I haven't worked on anything but al-Qaeda since."
Age of Terror: War on the West was broadcast on Tuesday, 6 May, 2008 at 2100 BST on BBC Two.