By bicycle to flying school, and by jet to mass murder

Until now, we have seen only fragmented glimpses of the men behind the horrific attacks last week - rows in a bar, a messy room, hurried departures from suburbia. Here, for the first time, Chris Blackhurst and Paul Lashmar, reveal the entire operation, from pilot classes through to the murderous conclusion

Maybe it should have been the bicycles that gave them away. Every day for five months the two men rode bikes from their rented house to the Florida flying school. True Americans don't ride bikes ­ not every day for five months. But then the pair who turned up on time every day for Rudi Dekkers' pilot class weren't true Americans.

Mohamad Atta and his buddy, Marwan al-Shehhi, were on a mission. They had to learn to fly a plane as soon as possible in order to kill as many people as possible.

Every responsible parent teaches a child that if you work hard at something you will achieve your goal. Last Tuesday, the diligent, bicycling pair got their reward. Most times, they did not go to bars like other students, noted the house's owner, Charlie Voss. They just wanted to learn about flying.

In truth, there were plenty of clues that last Tuesday's hijackers were not of the usual world. They paid $10,000 each by cheque to attend Huffman Aviation International flying school at Venice, yet, despite that outlay, they lived frugally. People who train to be pilots are often gregarious types, hard socialisers. But this pair were serious and inward, not mixing, sitting apart from the rest.

At Mr Voss's house, the two also paid good money, but also behaved oddly. Neat in appearance for school ­ would-be pilots are always immaculately turned out ­ their room was a tip. In Venice, a small, clean, town 80 miles south of Tampa, they annoyed the house-proud Dru Voss by shaking their hair dry all round the rooms when they stepped out of the shower.

In Vero Beach, also in Florida, a man known as "John" was also learning to fly, and putting the rubbish out and mowing the lawn and doing what normal people do. But John, whose real name may have been Amer Mohammed Kamfar, was not normal, either. The clue, in his case, was the way he suddenly packed the woman who may have been his wife and the four children who may have been his children into a van three or four weeks ago and drove away. Next door, Hank Habora could not help noticing they put everything, even Tupperware, out with the rubbish.

"John" turned up again, on board one of the planes that took off from Boston's Logan airport and became weapons of mass destruction.

Mohamad, Marwan and Amer are names that have become ingrained on minds the world over. While they, if their creed is to be believed, enjoy the delights of 72 virgins each in paradise, having martyred themselves for Allah, the rest of the world can only pore over the clues they left behind.

If they could talk they might tell us why they did it, that they parked their car at Logan next to the cars of people they intended to kill, how they sat in the departure lounge, a group of regular guys like those alongside them, who, they knew they were going to murder.

That is one of the funny aspects of airports. You arrive as strangers and leave as strangers, but in-between, you share an experience. You queue up together, you go through security together, you sit near each other at the gate, you may even sit next to each other on board.

If the men had second thoughts, a doubt about what they were about to do, they did not show it. The cctv cameras from that fateful day reveal nothing out of the ordinary. A group of men behaving quite placidly, not attracting attention, not alerting anyone watching that everything was not as it seemed.

If there is another characteristic of Tuesday's events, in addition to the sheer bloody cruelty and, it has to be said, the audacity, it was the careful planning. At the very end they could afford to leave clues behind ­ they knew they weren't coming back ­ yet in that long build-up they left nothing to chance.

They arrived for their final hours in groups, at Boston, Dulles and Newark. Two of them had been seen hanging round Logan, watching and examining for at least five days beforehand. Each airport was carefully chosen. They were busy with plenty of flights, plenty of nationalities passing through. The terrorists also chose the quietest day to fly in America, a Tuesday, when security checkers are that little bit sleepier, when the authorities would be least expecting an attack.

The hijackers chose eastern seaboard airports, so ensuring a short flying time to their targets, and they picked long- distance flights because the aircraftfuel tanks would still be full. The full tanks meant that when they crashed, the aircraft would behave like huge bombs. A 767, when fully tanked, has the destructive potential of a one-kiloton nuclear device. And they chose internal US flights, where security was slight. At Boston, the hijackers picked AA11 and UA175, both to Los Angeles. At Dulles, AA77 to Los Angeles was their missile, and at Newark, UA93 to San Francisco was selected. Some of them bought one-way tickets.

It is likely that they, or their helpers, had been on the flights before to check them out and had been through security. They knew what was possible to take on board, and what was not. In the event, they took little in the way of weapons ­ some small knives, box knives (the American equivalent of Stanley knives), nylon line to tie the crew up with as they stabbed them to death, and boxes they would tellthe terrified and, in the case of three of the four aircraft, cowed, passengers were bombs.

Their destinations were not just symbols of power, they were also easy to spot from the air. At least one target, the World Trade Centre, features in a software air simulator package for planes flying over New York, and it is easily available from computer stores. They could have rehearsed the attacks in precise detail. And they arrived in dribs and drabs, using short-hop, connecting flights, ferries and rental cars.

In total, says the Justice Department, there were 19 terrorists on the planes (investigators believe that there could have been as many as 30 in all, including some who stayed behind). They met up at hotels near the airports. At Boston, they chose the smart Westin and the Park Inn (there, police later found a car containing flight manuals and a book on how to fly a 767). At Newark, they went to the Airport Marriott. Some of the hijackers had known each other for years, but others were relative strangers. Even so, their security was solid. Not one of them turned informer. Police are working on the theory that the plan was finalised well away from the US, possibly in Hamburg, where Atta, al-Shehhi and, it is believed, others had been students. Even so, to have so many people involved in one huge crime and for not one of them to break ranks was almost incredible, and serves to underline the complexity and scale of the task that now faces investigators.

Only on the very eve of their "martyrdom" did the hijackers draw attention to themselves. At Boston, one group became involved in a minor altercation with the occupants of another car as they parked. Yet, in the same way that Atta had almost been thrown out of Shuckums bar near Miami the previous Friday, the parking dispute did not prove a problem.

That day, Atta had been drinking vodka and orange in the afternoon while Marwan nursed rum and Coke. There was a third man, so far unidentified. They were arguing among themselves, but this was America and they were speaking Arabic, so nobody listening in understood what was being said. Two Arabs having a load of drinks in the middle of the afternoon, ahead of the weekend, having a falling out? It happens.

Atta queried his $48 bill, for the 10 drinks for himself and Marwan, and things got nasty. When the manager, Tony Amos, came over to see what was wrong he produced a wad of $100 and $50 bills and paid. But not before cursing Amos: "You think I can't pay my bill? I'm a pilot for American Airlines. I can pay my fucking bill." This is Miami, people are rude to each other, especially after consuming five drinks. It is normal.

So it was in the parking lot. Raised voices as people struggle to find a space can be heard all the time.

The planes were selected so as to be airborne close together. One hijacking was believable, but two, three, four? Impossible. In the event, all the aircraft took off as usual. On AA11, stewardess Sara Low would have been thinking about preparing breakfast for passengers when Satam Al Suqami, Waleed al-Shehri, Wail Alsheri, Atta and Abdulaziz Alomari suddenly produced knives and took control. The aircraft changed course and headed for New York and the north tower of the World Trade Centre.

On UA175, the scene was repeated. Some from the group including Marwan, Ahmed Alghamdi, Hamza Alghamdi, Fayez Ahmed and Mohald al-shehri attacked a stewardess, stabbing her. Peter Hanson called his father in Connecticut: "Something's wrong with the plane. Oh my God! They've stabbed the air hostess. I think the airplane is being hijacked." The line went dead. Soon, the plane crashed into the south tower.

On AA77, five passengers later identified as Khalid al-Midhar, Majed Moqed, Nawaq Alhamzi and his brother, Salem, and Hani Hanjour produced knives. They gestured for their fellow passengers to move to the back of the plane. In the lavatory, Barbara Olson, a television reporter, locked herself in and called her husband, the US Solicitor General, and said the plane had been hijacked by men carrying knives. They are thought to have attacked stewardesses to draw pilots, including AA77's Charles Burlingame, out of the cockpit. As soon as the pilots emerged, the hijackers are believed to have rushed in, taking the controls. The first thing that they did was switch off the alarm that would have alerted ground control of anything untoward.

However, on AA11, pilot John Ogonowski somehow managed to stay in control long enough to warn those back on ground that his plane had been taken over. Ogonowski repeatedly pressed the "push to talk" button on his radio which allowed controllers to hear what was going on in his cabin. "There was this voice that was clearly threatening the pilot," said one controller.

Of the four flights, Captain Jason Dahl's aircraft, UA93, is thought to have had a smaller complement of hijackers. Four were involved: Saeed Alghamdi, Ahmed Alhaznawi, Ziad Jarrahi and Ahmed Alnami. Perhaps because there were only four terrorists, those on board, possibly including stewardess and former police officer CeeCee Lyles, quickly decided to try to overcome their captors. Thomas Burnett called his wife four times from his mobile phone, to say he was leading the fighting. He was joined by Jeremy Glick, who told his wife that he had "decided to go down fighting". He told her the hijackers had "already knifed a guy" and claimed to have a bomb on board.

Then he rang off. The plane turned violently, possibly to head for Camp David or towards Washington and the White House or for what would have been a double strike on the Pentagon. Within minutes, however, it had crashed, plunging into countryside outside Pittsburgh.

Inside the mind of the suicide bomber

By Paul Lashmar

There is a telling moment in The Terrorist, the recent acclaimed film, where the resolve of the central figure – a would-be suicide bomber – suddenly falters. Malli, the 19-year-old woman who has already ruthlessly killed and is about to assassinate her country's leader, discovers that she is pregnant. The realisation that she is carrying a new life makes her question her mission to murder in the pursuit of her ideology, an act that would inevitably destroy her.

Director Santosh Sivan's debut film provides a rare insight into the mind of the bomber. While in the West we tend to see these people as mad, in nearly all researched cases they are quite sane. The Israeli terrorism expert Ehud Sprinzak has dubbed them the "rational fanatics".

"While most of the world sees suicide terrorists as lone, irrational zealots, they are, in fact, pawns in large terrorist networks that wage calculated psychological warfare," he says. Israel has more experience than any other country of suicide attacks. Since the peace accords in 1993 there have been more than 14 Hamas suicide attacks, killing more than 200 people and wounding hundreds more, mostly Israelis.

Experts say there are two types of motivation for the bomber. The first involves anger and a sense of hopelessness. Typical is Samir Toubasi, a 19-year-old Palestinian, caught while driving to a disco with a 22lb bomb. He was ready to kill himself and as many Israelis as possible. "I lost my job, my future, my hope," said Toubasi. "Then Israeli soldiers killed my friend. I wanted to die."

Boaz Ganor, executive director of the Institute for Counter-Terrorism, says that suicide attacks are considered attractive by groups of religious and nationalistic fanatics who regard them as part of a "holy war". He says that the Hamas suicide bomber tends to be young – usually aged between 18 and 27 – unmarried, unemployed and from a poor family, but with a high school education. Experts also say that such attackers usually have close friends or relatives who have been killed or brutalised by Israeli security forces.

In addition to the religious mission, Mr Ganor says, the shahid or martyr also receives some personal benefits, including eternal life in paradise, permission to see the face of Allah, the favours of 72 virgins in heaven, and also earns a privilege to promise a life in heaven to 70 relatives.

In order to make sure the bomber does not change his mind, the terrorist organisation creates points of no return. Dr Ariel Merari of Harvard University says: "These are achieved by making him write last letters to his family and friends. He is videotaped saying farewell and, from that point on, he is actually referred to in Arabic as al-shahid al-hai, which means the living martyr. As a living martyr, he is already dead."