On February 5, about 2.30pm, a man dressed in a police SWAT-style uniform ran into the foyer of Dublin's Regency Hotel and fired his AK-47 at the roof.

He was the point man of a six-strong hit squad (two were already inside the hotel, armed with pistols, one disguised in drag with a blonde wig).

The hotel was hosting the "Clash of the Clans" boxing bout weigh-in. The attack sparked immediate panic – though a boxer in his underpants had the presence of mind to grab his trousers. As boxers, trainers and bystanders fled the building a terrified little girl could be heard crying, "Daddy, help me ... Daddy, what was that?"

It was an extraordinary public assassination, a new chapter in an escalating Dublin gangland feud that has left nerves in the Irish capital on edge, and has more than one career criminal wondering if their number is up next.

Among the crowd fleeing the hotel was Daniel Kinahan, who managed some of the boxers. He is the son of a man dubbed the "Irish Godfather' – believed to be the head of a drug and money-laundering racket worth hundreds of millions of euros and stretching across Europe and beyond.

It was a lucky escape for him – but not for his favoured lieutenant, David Byrne, 33, from Dublin's Southside, who was left "riddled" with bullets in the lobby.

Byrne's funeral on Monday was extraordinary.

The Kinahan gang's finest mobsters turned up to the lavish event: David's father, James "Jaws" Byrne, Daniel Kinahan and his brother Christy jnr, cousin "Fat" Freddie Thompson. The Chosen Few bikers led the hearses, which were followed by 10 stretch limousines and three horse-drawn carts stuffed with huge floral wreaths, boxing gloves and written tributes. Gaping locals and tourists lined the streets.

At the church a remote-controlled toy BMW with a picture of Byrne poking out of the roof zipped ahead of a platinum-plated, €18,000 ($28,000) coffin.

The priest castigated the gathered thugs. "What courage is there to walk into a hotel and blast a man to death when he cannot defend himself?"

He called for a "hero" who "will bring peace again to our beautiful capital city and an end to the policy of violent death, revenge and tit-for-tat".

Finally, a lone piper played Hard Times Come Again No More.

About 100 police stood guard, searching for bombs, surrounding the church and keeping an eye on the homes of potential revenge targets.

They were well aware that this had not been a one-off settling of an underground debt. The feud was threatening to erupt into a war.

Jim Cusack, crime reporter for Dublin's Sunday Independent, says the crime scene in Dublin is "not very complicated".

On the one hand there's a "very major gang" – the Kinahans. And on the other there's a "big old gang" and that's the Hutches – formerly headed by Gerry "The Monk" Hutch.

The Hutch gang have been linked to two infamous cash heists – £1.3 million taken from a security van in Dublin's north in 1987, and in 1995 £2.8 million robbed from a cash holding facility in north county Dublin.

The Criminal Assets Bureau managed to squeeze €1.5 million out of The Monk but couldn't pin a crime on him.

But the Kinahans are the bigger fish.

"They're massive," Cusack says.

He believes they have made Ireland the main gateway for drugs into Britain: "We have 200 customs officers to cover all ports and airports. I'm told large shipments are regularly dropped off the unprotected west coast, collected by fishing boats and moved through the Republic to the UK."

Another veteran Dublin reporter, Tom Brady, has been covering crime or security for more than four decades. He agrees with much of Cusack's assessment. "Christy Kinahan [snr] would be one of the biggest drug dealers in Europe at this stage," he says. "His empire reaches right into South America."

Kinahan was bright – according to one gangland legend he once refused parole so he could finish studying for a degree in prison. "They were using Spaniards and Dutch and Spanish middlemen to buy stuff off the likes of the Colombians. They realised that they could do without the middlemen and started to move to Spain and made direct contact with Colombians, cut out the middlemen altogether and started to make huge money."

They are also big in the cut-flower business.

These days they're based down in Marbella in Spain – an area dubbed the "Costa del Crime" for its concentration of international baddies – Russians, Turks and others.

Part of the reason for the move dates back 20 years. After investigative reporter Veronica Guerin was gunned down on the street, Ireland established the Criminal Assets Bureau and many "celebrity criminals" fled to Spain or the Netherlands to protect their ill-gotten gains.

Those in the know trace the current feud back to last September, when Gary Hutch, 34, was gunned down beside his swimming pool in the gated Angel de Miraflores complex near Marbella.

Once an associate of Daniel Kinahan, Gary Hutch fell out of favour amid rumours he'd turned informant to the Spanish police (there were also reports he owed the Kinahans money).

Gary Hutch was the nephew of Gerry "The Monk" Hutch.

According to one report The Monk had negotiated with Christy snr to have the contract on Gary's life cancelled in exchange for €200,000.

But Daniel, The Irish Sun reported, "became aware of an alleged threat to his own life and reneged on the agreement".

Christy Kinahan is said to have passed control of his criminal empire to his eldest son, Daniel, last year. But he is also reported to be appalled by the consequences.

According to several reports he didn't sanction the hit on Gary Hutch.

One source told the Irish Sun: "Christy Kinahan managed to stay more or less under the radar for almost two decades. Daniel is in charge for a wet week and the whole thing is in chaos."

Cusack is even more blunt.

"[Daniel] is a f---in' eejit," he says. "[It was] a problem with the new management, with the son, as always happens when you pass on an organisation to a half-witted family member. So that's what basically happened – Daniel's a f---ing shithead and he's surrounded by shitheads."

It reminds him of the time half a decade ago when a man named Eamon Dunne became Dublin's biggest crime boss.

"In 2009 he decided to take over the whole city and kill everyone. He based himself on the character Marlo in The Wire and set about killing all opposition. And then in 2010 he got killed. About everyone in Dublin agreed it was time for him to go – it's one of those murders where you have a very large list of suspects."

Hardy says: "Kinahan realised this was bad for business and he's supposed to have been behind Dunne's death. He's ruthless and everything is to do with the business."

According to the Hutch clan (who issued a statement to the media), "Gary had a falling out with the Kinahan organisation.

"This matter was resolved and €200,000 in cash was paid over. We shook hands and agreed to walk away. Gary was then murdered for no reason. You cannot trust these people."

In early January The Monk had a narrow escape: two balaclava-wearing gunmen burst into a pub in Lanzarote in Spain, just minutes after he had left.

He was said to be "unimpressed" with the murder of his nephew Gary – and with a six-figure sum the Kinahans were said to have offered to end the feud.

But the Irish Independent reported he "had no prior knowledge" about the revenge hit on the Regency – and was furious with those who planned it.

The main reason he's furious is because of what, predictably, came next. Tit for tat.

On Monday, February 8, thugs chased 59-year-old father of five Eddie Hutch, Gerry's older brother, into his Dublin home, finishing him off in the living room. "He got about three or four bullets all into the head," his sister-in-law said. "It was the worst thing in the world. There was blood all over the walls."

According to one report the killers screamed "That's for David" as they gunned him down.

The Monk – it is said – has let it be known that "all bets are off" with the murder of his brother. He snuck back into Dublin and turned up in disguise on Friday to the funeral.

And the risk is spreading. Police have notified some Irish journalists that their safety is at risk from organised criminals. Independent News Media managing editor Edward McCann said his organisation had lost two journalists in the last 20 years – "Veronica Guerin and then there was Martin O'Hagan​ in Northern Ireland so we're well aware as a group of the dangers posed to journalists."

Ireland is in the middle of an election campaign – and the murders were seized on as an issue to tackle the current coalition partners, Brady says (though it is already returning to the usual "economy and healthcare" debates). It also spiked the tyres of Sinn Fein, which had been campaigning on a promise to abolish the Special Criminal Court, set up to deal with organised crime and terrorists.

The Irish Mirror reported that both MI5 and MI6 have come in to help unravel the Dublin crime scene – partly to stop them using London for money laundering.

The president of the Garda (Police) Representative Association Dermot O'Brien​ said there weren't enough resources to take on gangland crime. He told morning radio he wanted "more dedicated recruitment" and for detectives to get new submachine guns.

Says Cusack: "The police here have a success rate of one in 10 in solving gangland murders. They've kind of imploded. They've had lots of problems over the years and they've really given up."

A Garda spokesman told Fairfax Media: "We don't comment on ongoing investigations."

On Thursday it was reported that The Monk had attended a "peace summit" in Amsterdam with the Kinahan crew

Brady says "heat is bad for business" and this may end the feud. It's most likely the action will "swing back to Spain". There's too much at stake for the gangs to be distracted by murders for long.

But, he points out, "at the moment the Hutches have lost two of their family and the Kinahan cartel have only lost one of theirs – who wouldn't be in the top tier. [The Hutches] might feel it needed another murder to level it up, make it two-all."

And you never know, Cusack says. The Kinahans may want to protect the women and children in their cut-flower business.

"If the Kinahans decide they want to wipe out the Hutches then we've got loads of f---ing fun coming up."

WHO'S WHO

Christy 'Dapper Don' Kinahan

Police believe he built a drug empire, one of Europe's biggest. Ruthless but business-focused. The 57-year-old, born in Dublin's inner south, now lives in Spain.

Daniel Kinahan

The Dapper Don's 36-year-old son – boxing coach and allegedly the heir to his father's empire.

Gerry 'The Monk' Hutch

Became notorious after he was accused of masterminding two of Ireland's biggest cash heists. In 1999 he paid the Criminal Assets Bureau €1.5 million in tax on his "substantial criminal wealth". Reportedly "no longer involved in criminality".

Gary Hutch

Nephew of Gerry. Shot dead at the Miraflores on the Costa del Sol, September 26, 2015. A career criminal and – latterly – suspected to be a police informer.

David Byrne

Notorious criminal and "significant" Kinahan lieutenant, shot dead at Dublin's Regency Hotel in February 2016. A leading "mover" who travelled between Dublin and Spain.

Eddie Hutch snr

Taxi driver, brother of The Monk, convicted fraudster and thief but not known as a violent criminal. Shot dead at his Dublin home, February 8, 2016.

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