Dubliner David Byrne, who was shot dead by a gang of six men at the Regency Hotel in Dublin on Friday, had close links with an international Irish-led crime cartel.

The man understood to be at the head of that gang, Christy Kinahan (57), has drug and money laundering convictions in Ireland, the Netherlands and Belgium.

Kinahan has had Irish addresses at York Street and St Teresa’s Gardens in Dublin’s inner city, as well as at Cabra, Phibsboro and Fairview, all on the north side of the city, but he is now based in Marbella in southern Spain.

Crime agencies regard him as the biggest wholesaler of illicit drugs for Irish crime gangs.

Despite being subjected to a major international law enforcement investigation and co-ordinated raids all over Europe, including in Ireland, five years ago, he remains at liberty.

Kinahan grew up in a block of council flats in St Theresa’s Gardens in Dublin’s south inner city. He is from a highly respected family, one member of whom is well-known in the Irish trade union scene.

Christy Kinahan's first convictions date back to the late 1970s and involved house breaking, car theft, burglary, handling stolen goods and forgery.

His first major conviction related to the seizure in Marino, north Dublin, of heroin valued at £117,000 in 1986, for which he was jailed for six years.

From that beginning, Kinahan operations have expanded to a point where he is now considered to be the key wholesaler of drugs to the Irish market. Kinahan’s operation also supplies gangs in other countries, including the UK.

Kinahan knew most of the men at the top of the organisation from the crime scene in Dublin, or got to know them while supplying drugs to Irish gangs.

He is understood to have amassed a vast personal fortune over the last 15 years through drug-dealing, and investing and laundering the proceeds of his crimes.

Kinahan’s early days

Regarded as one of the most intelligent Irish criminals involved in the international drugs trade, Kinahan speaks several foreign languages, including Dutch and Spanish.

During a prison term in the 1990s he studied for a degree course in French and refused temporary release so he could complete it.

In March 1987 he was jailed for six years after pleading guilty to possessing heroin valued at £117,000. He told the court he was a heroin addict and was trying to turn his life around by studying in prison.

In March 1998 he was jailed for four years after he was found in possession of £16,000 in stolen travellers’ cheques.

Kinahan, a separated father-of-three, also has convictions for forgery and for possession of cannabis.

He served at least one of his sentences in the State’s maximum security prison in Portlaoise. He was released from his last prison sentence in 2001 and is believed to have left for Spain within months.

He has a villa near Marbella which had an estimated worth about €6 million at the height of the property boom there, and also regularly uses a nearby apartment worth in the region of €1 million.

He is a high-stakes gambler and is also suspected of involvement in fixing horse races he bets on.

On moving to Spain almost 15 years ago, he immediately established international drug-dealing contacts there.

He began sourcing massive drug shipments from Colombian, Spanish and north African cartels for sale to Irish criminals.

He has served jail sentences in the Netherlands.

Just over five years ago he was convicted of money laundering in Belgium, and jailed for four years.

However, he was granted bail pending an appeal, which was due to be heard in April 2010.

1: Regency Hotel: scene of gun attack which left one dead 2: Charlemont housing estate: burned-out getaway van found at rear of estate 3: St Vincent's GAA club: gunmen believed to have escaped through grounds

He was arrested in Belgium in May 2008 after authorities there traced cash and assets owned by him to the value of €2.5 million.

Kildare drugs haul

When a consignment of his cannabis was found in a commercial premises in Co Kildare in 2008 it began a chain of events that put his enterprise to its biggest law enforcement test yet.

On that occasion, in February 2008, gardaí searched a warehouse at the back of a house in Clongorey, Co Kildare, and seized one tonne of cannabis.

A further 500kg of the drug was seized in a car in Kill as part of the same operation, bringing the value of the drug seized to €10.5 million.

Four men were arrested at Clongorey, an industrial estate near Newbridge and in a vehicle in Kill.

Three firearms were also seized, including a rifle with a telescopic sight and silencer, a pump-action shotgun and a single barrel shotgun.

Two Irishmen were convicted for their role in the Kildare find, and two others who were charged went on the run. One is a former League of Ireland soccer player.

When gardaí began looking into the background of the Kildare haul, a very interesting picture emerged.

They found it was linked to a group of Irish criminals - led by Kinahan - based in Malaga and Marbella, in southern Spain.

These men had set up small food companies and started importing inexpensive foodstuffs from Spain.

Once they had established a record of having imported shipments of food into small warehouses in Ireland on vehicles registered to their company, they began smuggling drugs on those food export runs.

The property in Clongorey included a warehouse with forklift and trucks, all being used to move large consignments of drugs quickly around the country once they had entered Ireland from Spain in trucks on car ferries.

Once here, the drugs, mainly cannabis and cocaine, were sold on wholesale in multimillion-euro batches to crime gangs nationwide.

Up to that point, in early 2008, Kinahan had not aligned himself to any one gang in Ireland.

He stayed out of gangland feuds here and simply acted as a wholesaler to all of the main players. These include key drugs gangs in Dublin, Limerick, Cork and in the regions.

Investigation moves to UK

The Garda’s investigation arising from the Co Kildare cannabis find in February 2008 identified an identical operation run by Kinahan in England.

It was centred mostly in the greater London area, where front companies with vehicles and small warehouses were used to ship in drugs from Spain.

An international investigation led by the Garda and supported by the authorities in the UK found the front companies in both jurisdictions were linked to a parent front company in Spain.

All of these companies were controlled by Kinahan and those around him.

Information supplied by the Garda to the London Metropolitan Police resulted in the seizure in March, 2009, of eight semi-automatic firearms, four machine guns and ammunition and silencers.

The UK police believed the guns originated in Spain and were shipped via the front companies. The UK police were now as interested in Kinahan as the gardaí.

In Spain, things began to get serious for Kinahan from the time of the Kildare drugs find in February 2008.

Indeed, in the same month members of the Kinahan gang shot dead Paddy Doyle near Marbella. He was a 27-year-old from Dublin’s north inner city and was a chief suspect for at least three murders committed as part of the Crumlin-Drimnagh gangland feud.

When the Spanish police began investigating that killing, they quickly realised gardaí were unpicking the background and modus operandi of the same gang it believed shot dead Doyle.

Co-ordinated raids internationally

In May, 2010, after more than two years of international investigation into the Kinahan gang arising from the Kildare cannabis seizure and the Doyle murder in Spain, police forces in a number of European countries moved against the Kinahan gang with co-ordinated surprise raids and arrests.

A total of 700 police officers from across Europe began to kick in the doors of business outlets and residential properties where the gang leaders, including Kinahan, were sleeping.

The investigation focused not only on drug-trafficking but on the money-laundering and property investments in which Kinahan, who was arrested at his Marbella villa, was involved.

Gardaí believed the gang led by Kinahan was not only laundering its own money and buying property for itself but had also acted as a financial services agent for other criminal gangs.

At the time of the May 2010 raids, under Operation Shovel, properties owned by Kinahan and his associates were identified across the world and have an estimated combined value of over €150 million.

The properties were mainly residential but include some business interests such as pubs and small retail businesses.

Properties were traced in Ireland, Spain, Belgium, Dubai, South African, Brazil and Cyprus. A network of solicitors and accountants in all of those jurisdictions have been used to buy property.

However, while the arrests of Kinahan and his associates and the discovery of how so much of his operation worked was billed as a spectacular breakthrough at the time, Kinahan and his associates were released without charge.

The huge investigation was unable to find enough direct evidence to link the key men to specific crimes they could be charged with.

And in the five years since, it has been business as usual under the Spanish sun for Kinahan.

Gary Hutch and Regency Hotel

When the Operation Shovel raids were taking place during the last week of May 2010, only one person was arrested in Dublin despite a large number of searches there.

That suspect’s name was Gary Hutch - the Dubliner from the north inner city who members of the Kinahan gang would fall out with and murder in Spain last September.

Hutch was 34 years old when he was shot dead beside the pool at an apartment block, Angel de Miraflores, near Marbella, on the Costa del Sol.

His murder effectively began a feud between his large group of associates in Dublin and members of the Kinahan gang in Spain and its associates in Dublin.

Gardai believe Friday’s attack at the Regency Hotel in Drumcondra, north Dublin, was an attempt by Hutch’s associates to target members of the Kinahan gang who were in Dublin.

The man shot dead, David Byrne from Crumlin, split his time between Dublin and Spain. The gunmen are understood to have targeted him.

The another target was Kinahan’s son, Daniel Kinahan, who had travelled from Spain for the boxing tournament due to take place in Dublin on Saturday night - the weigh-in for which was the scene of Friday’s hotel shooting.

The savage and well-planned nature of the attack essentially puts those loyal to Gary Hutch at odds with members of the Kinahan gang in an all-out underworld feud.

Any members of the Kinahan gang living in Dublin or even spending some of their time in the city are expected to flee to his base in Marbella, at least for the time being.