Conman, escape artist, expert linguist, possessor of hypnotising charm, a dozen aliases and a bunch of false passports . . . and wanted by police on at least three continents . . . Betancourt knew exactly what he needed to do. It had worked countless times before, in some of the world's grandest hotels, from Tokyo to Las Vegas, via Paris and London.

Born in Colombia, and often claiming to be the son of a diplomat or a German prince . . . neither of which, like most things in his life, had anything to do with the truth . . . Betancourt had enjoyed a good run. In a 10-year career as perhaps the world's most accomplished international conman and hotel-thief, he had never been caught redhanded. What he was about to do that morning at the gracious, five-star Merrion was tried and tested stuff.

When he walked in he was wearing jeans and a T-shirt bearing the slogan 'Save Water . . . Drink Beer'. He usually dressed in stolen Valentino or Armani, and this was a risky outfit, but then all sorts of rich scruffs stay in smart hotels.

For the first 40 minutes or so, it's unclear what he did in the hotel. He was picked up on CCTV making . . . or perhaps pretending to make . . . a phonecall in the lobby, but that was it.

By around 10.15am, though, he was in a top-floor corridor where he met a cleaner coming out of the 1,000-a-night Kirk Suite. An American couple, their children and the children's grandmother, from Beverly Hills, were staying here.

Betancourt told the cleaner he had forgotten his room key and asked if she could she let him in. She said she couldn't, but as he chatted to her, switching on his charm, she mentioned that she would be doing some babysitting for the family in the suite that night. Betancourt would use this scrap of apparently irrelevant information in a brilliantly skilful way.

He went down to reception. There he took his usual gamble . . . that in a big hotel, not every staff member will know every guest by sight. He explained to the desk clerk that he was staying in the Kirk Suite but had stupidly mislaid his key card. With his deft and deadly charm, he left the clerk in no doubt that he was a genuine guest. As he walked away with the 'replacement' key card, he turned and casually asked: Are we still OK for the babysitter tonight" The babysitting booking had already been made and was there in the log. Who would suspect a thing?

Once in the suite, Betancourt telephoned downstairs . . . not to the reception desk where he'd just been, but to the hotel's operator. Knowing that the guests had young children, he told the operator that his kids had been playing with the combinations of the suite's two safes, and that they now wouldn't open.

Might someone come up and unlock them for him When one of the security staff arrived, Betancourt spoke to him in an American accent. The whole thing seemed so convincing. And why would Betancourt even be in the suite if he wasn't a legitimate guest? The guard opened both safes and left.

In the safes, Betancourt found an American passport, almost 3,000worth of dollars and euros, a ruby ring, and an American Express card. He took the lot, locked the safes by inputting his own seemingly random codes, and left.

He strolled out of the hotel and along the north side of St Stephen's Green to Grafton Street. In HMV, with the stolen Amex card, he bought a pile of CDs and DVDs worth around 700. In Brown Thomas, he bought around 1,000worth of designer clothes. But his first stop had been Weir and Sons, established in 1869 and Dublin's grandest jewellers. With the hot American Express card, he hit Weir's for an 18-carat white gold Rolex Daytona, worth about 16,000.

Even when the purchase was briefly queried by American Express, Betancourt stayed ice-cool. When the card was swiped, it gave a refusal, " says Weir's managing director David Andrews. So you have to ring for a sanction number, and in a lot of cases they will ask to speak to the holder to ask for some personal detail. In this case they didn't, and gave the sanction.

months into a three-and-a-half-year sentence for a near-identical £40,000 burglary at the Mandarin Oriental Hotel in London.

After saying he needed to go to the dentist, he had been allowed out of Standford Hill . . . alone, as is permitted in an open prison. He turned up for the dental appointment but then kept going.

Somehow, he made it off the Isle of Sheppey in the Thames Estuary (there is only one route to the Kent mainland, by bridge) with, reportedly, no money and no credit cards but, in typical style, wearing a pair of Cartier sunglasses.

The papers would later be full of it.

'Flamboyant jewel thief cons his way out of prison, ' ran one headline.

Despite an alert at all ports and airports, just over a week later he was in Dublin. How he got there is a mystery.

Even seen-it-all detectives say they have grudging respect for his skills as a thief, liar, con artist, linguist and forger . . . and for his ability to get out of tight spots.

He'll nick or forge anything, nailed down or not, " says one. They often compare him to Frank Abagnale Jr, the breathtakingly bold American former conman played by Leonardo DiCaprio in the film Catch Me If You Can.

The problem for police across the world is that, while he is not nearly as inventive as Abagnale in his range of cons, Betancourt, it could be argued, is just as smart. No one knows how much he has netted in a trail of heists at fivestar hotels around the world, stretching back to the mid-1990s. One guess puts it close to 1.5m, but it's probably more.

And his favourite targets were London's big hotels.

Andy Swindells, a detective sergeant around, have a coffee, change some money. Hotels are small communities, and the reception staff see people all day long. If you change money a couple of times, they'll remember you." And, crucially for Betancourt's plans, they'll think you're a guest.

Swindells says Betancourt would pick up guests' names and room numbers from discarded bar tabs, or from gym bookings, or by overhearing staff greeting guests. You can stand in the breakfast queue and hear people say: 'I'm Mr So and So' and the staff will ask for the room number, " says Swindells. Once he'd got those details, he would go to reception, to the same person he had dealt with earlier when he changed money, and say: 'Hello, I'm back again.

I'm Mr So and So in room Such and Such and I've lost my key card; can I possibly have another one?' Because the staff recognise him and because he knows the name and the room number, out of deference the staff may not ask for any identification. There's a culture in hotels of 'the guest is always right'."

Betancourt played ruthlessly on this fact. Once he'd got into the room, he collected whatever he wanted, " says Swindells. Then he would phone security and say: 'Hi, I'm Mr So and So, I'm in my room and I'm so sorry, but can you come and open my safe? I've forgotten the combination.' What's more plausible than that? It's not unusual for people to forget the code they've put in.

And with his charm and nice clothes and flashy watch, why would anyone be suspicious?"

But there were some close calls.

Betancourt was first arrested in Britain in 1998 on suspicion of four burglaries at arrested at Heathrow airport after trying to buy goods in an airport shop using a credit card stolen from a hotel room in Tokyo. He gave his name as Cesar Ortigosa Vera . . . and had ID to back this up.

In court the next day he pleaded guilty, was fined £400, paid it in cash from a wad of notes, and walked out. His luck was that, at that time, the Metropolitan Police did not have an automated fingerprint system. It was only later, once he'd gone, that it became clear that card-thief Ortigosa Vera and bailjumper Zapater Vives were the same man.

By May 2001, Betancourt was back in London. That month alone he allegedly hit the Lanesborough and Mandarin Oriental hotels in Knightsbridge, and the Four Seasons and Intercontinental hotels in Park Lane. His haul from the Mandarin Oriental burglary was £40,000 in jewellery and cash. At one of the other hotels he is reported to have stolen £15,000. After the Intercontinental theft, which included a guest's Amex card, he was clearly in the mood to celebrate, using the card to hire a chauffeurdriven Bentley to take him to Heathrow (cost: £400). There, on the same card, he bought a ticket to Paris and blew £8,000 on a pile of jewellery and designer clothes at the shops in the departure lounge.

Then he disappeared again until August 2003, when he showed up in Las Vegas, and allegedly pulled off what may have been his biggest heist. ?From one of the city's finer hotels, and from another hotel, he is alleged to have stolen cash IN court the next day he pleaded guilty, was fined £400, paid it in cash from a wad of notes, and walked out. His luck was that, at that time, the Metropolitan Police did not have an automated fingerprint system. It was only later, once he'd gone, that it became clear that card-thief Ortigosa Vera and bail-jumper Zapater Vives were the same man.

By May 2001, Betancourt was back in London. That month alone he allegedly hit the Lanesborough and Mandarin Oriental hotels in Knightsbridge, and the Four Seasons and Intercontinental hotels in Park Lane.

His haul from the Mandarin Oriental burglary was £40,000 in jewellery and cash. At one of the other hotels he is reported to have stolen £15,000. After the Intercontinental theft, which included a guest's Amex card, he was clearly in the mood to celebrate, using the card to hire a chauffeur-driven Bentley to take him to Heathrow at a cost of £400. There, on the same card, he bought a ticket to Paris and blew £8,000 on a pile of jewellery and designer clothes at the shops in the departure lounge.

Then he disappeared again until August 2003, when he showed up in Las Vegas, and allegedly pulled off what may have been his biggest heist.

From one of the city's finer hotels, and from another hotel, he is alleged to have stolen cash and jewellery worth, in total, over $350,000, " says Kirk Sullivan, a detective with the Tourist Crimes Detail of the Las Vegas Metro Police Department. ?He sometimes says he's descended from German royalty, and he sometimes uses the title Prince. This is all rubbish, but I don't know that anyone will ever know the truth about him."

Another Las Vegas detective reports that Betancourt would steal Rolexes from hotel rooms and use them for small change. ?He was giving those away as tips . . . for good service, he'd give a waitress a $50,000 watch."

By November 2004, Betancourt was in London yet again. This time he allegedly hit the Grosvenor House hotel in Park Lane, the Savoy, the Royal Garden Hotel in Kensington, and the Dorchester, where he would later admit to having stolen jewellery, cash and designer clothes worth £36,000 from the suite of a Bahraini businessman.

At the time, he was dossing down in the spare room of a council flat in Lisson Grove. What he was doing with all this money is a mystery. It's one of many in the strange and complicated life of Juan Carlos Guzman-Betancourt.

Though newspapers often describe him as ?the son of a diplomat", his mother was a cleaner and his father was a farm labourer in the fields around the remote Colombian country town of Roldanillo, where Betancourt was born in 1976. Roldanillo is set in the fertile Cauca Valley, which runs through the northern Andes, about 140kms north of Cali, Colombia's third-largest city. The little green-painted mud-built house where Betancourt was brought up is still there, about 15 minutes from town, in a small group of workers' homes beside the River Cauca.

Betancourt's father is said to have left home when the boy was about a month old.

His mother Yolanda subsequently married Harold Velasco, a clerk in an estate agent's office. She would later admit, in tears, that the young Juan Carlos had been badly treated at home. In his mid teens he left home, and would later claim he had lived in an abandoned plane at Cali airport, and grubbed in dustbins with other street children to feed himself. But shortly afterwards he was headline news.

In the early hours of 1 June 1993, he was found wandering and dishevelled at Miami airport. He claimed to be called Guillermo Rosales, aged 14, and said he had arrived from Colombia as a stow-away in the undercarriage of a cargo plane. How he survived the trip . . . or if his story was even true . . . has never been definitively explained.

According to newspaper reporter Luis Angel Murcia, a local correspondent for one of Colombia's national dailies, El Pais, there appears to be barely any trace of Betancourt's family in Roldanillo now, apart from a distant cousin who claims not to know him.

Betancourt's mother, Yolanda, is believed to be in Cali. Murcia has been told she scratches a living there taking in washing.

How, from such humble beginnings, Betancourt managed to become fluent in so many languages and pass himself off as a sophisticated global traveller is another mystery. Even detectives who have pursued Betancourt for years don't know.

The burglary at the Merrion wasn't discovered until the day after it happened, when the family in the Kirk Suite were packing to leave and found they couldn't open their safes.

The same security guard was called up to open them, and remarked that he'd done the same thing the previous day. The safes, of course, were empty.

After speaking with staff, Dublin detective Bryan McGlinn realised he was not dealing with a small-time local thief. He called American Express and seized CCTV footage from the shops where Betancourt had used the stolen card. He called all the city's big hotels to warn them, and visited all the B&Bs and backpackers' hostels in the city. It took him two days, non-stop. He was convinced that, to avoid immigration checks, Betancourt must have got to Dublin via Northern Ireland.

I figured if he had arrived from the North he would probably have come in near O'Connell Street where the bus and train stations are, and if he arrived there he would need some cheap hostel where he could keep his head down, " says McGlinn.

He was right. On Thursday, a tip-off took gardai to an internet cafe near O'Connell Street. Betancourt had been staying in a 50-a-night hostel nearby. In a backpack he had some jewellery, a laptop, an Austrian passport that had been stolen in Cork and the American passport stolen from the Merrion . . . expertly forged with Betancourt's own photograph. On his wrist was the Rolex Daytona he had got from Weir's. He admitted the Merrion burglary and two counts of theft by deception for using the Amex card to buy the Rolex, and the chain and ring from the second jewellers, John Brereton. But he claimed that he was Alejandro Cuenca, from Spain.

He's a nice guy, very plausible, very believable, and he admitted everything, whatever we asked. He's extremely convincing, " says McGlinn.

If I hadn't known better I would have been pretty sure that he was exactly who he said he was. He even has a tattoo of the Spanish flag on his arm. But we sent his fingerprints off to the Met and Interpol, who both confirmed they were Betancourt's."

A few weeks ago, Betancourt appeared in court in Dublin, wearing jeans and a blue jumper. Having already pleaded guilty, he was sentenced to two years for the burglary at the Merrion Hotel and was given two further sentences of 18 months, to run concurrently, for theft by deception of the watch and the jewellery. Also awaiting him on his eventual release is a European arrest warrant issued by the French authorities in connection with 13 offences allegedly committed in hotels in France. Others warrants are expected from the UK and the US.

When he was sentenced, Betancourt didn't react or say a word.

McGlinn recalls that in interviews with Betancourt it was when the fingerprint evidence . . . and thus his real name . . . was first put to him that his friendly demeanour totally changed.

After that, " McGlinn recalls, he just said: 'Nothing else to say.'"