Months of covert phone monitoring led to the conviction of an organised crime gang involved in the theft of artefacts worth up to £57m from museums and an auction house. But who were they and how were they caught?
Fourteen members of the gang have been jailed for co-ordinating the thefts of high-value Chinese jade and rhino horn taken in Cambridge, Durham, Norwich and Lewes, East Sussex.
The men, from Cambridgeshire, Essex, Kent, London, the West Midlands and Northern Ireland, were convicted of conspiracy to steal but it took months of "hard graft" to bring them to justice.
After a series of trials the gang members were handed jail sentences ranging from 15 months to more than six years.
Despite a four year police operation, many of the stolen items have not been found and the lead investigator admits they have also not found the "top person".
However, linking the various crimes led to several "significant players", some of whom were described in court as the gang's "generals".
Police were investigating a series of thefts when the gang's links began to emerge.
Back in April 2012, Det Supt Adrian Green, a murder detective with Durham Constabulary, was called in to investigate the theft of two Chinese artefacts from Durham University's Oriental Museum.
Because of the high value of the items, he was asked to oversee the case.
A jade bowl and figurine worth about £2m had been taken after thieves broke through a wall. They hid the items in scrubland - but then apparently forgot where.
"Unbeknown to us, the group that had planned and commissioned this - these were the hiring people - had written the whole of [that raid] off by 7 April," Mr Green said.
Police found the artefacts on 13 April but by that time the gang had moved on to a far more lucrative target.
Thieves broke into the Fitzwilliam Museum in Cambridge on 13 April, escaping with 18 mainly jade items which, together with the Durham artefacts, could have netted them up to £57m ($79m) on the "booming" Chinese auction market.
The following day Cambridgeshire Police called Mr Green asking if he had "any advice".
"Obviously then we had a relationship with Cambridge going forward," he said.
At this point the raids were formally linked by the method of entry and the kinds of items taken.
A jade water bowl from the Fitzwilliam "could definitely be a replacement for the one they didn't get [in the Durham raid]", Mr Green said.
In both cases the perpetrators were caught and jailed, but who was masterminding these audacious crimes?
'Pattern of panic'
The telephone that would be key to the gang's downfall was discovered as a result of the Durham investigation - found stuffed inside one of the suspects' underpants.
Lee Wildman and Adrian Stanton were arrested for the raid, in Walsall, West Midlands, on 1 May 2012.
"Telephony was worked out. One handset was recovered from Wildman's pants... and that's how we started to put [this] together," Mr Green said.
Investigators noted a flurry of telephone calls and texts began as soon as the items stolen from Durham were apparently "lost" in the scrubland.
"You get a load of telephone calls pinging here, there and everywhere which kind of showed they were trying to get hold of the burglars from the Durham museum," Mr Green said.
The calls "showed a pattern of panic" and one that made officers believe they "were in more of a controlling management position".
"You start to understand that there's another group in play here."
Several other people were arrested in the same area as Wildman and Stanton and links were being made between those involved in both the Durham raid and the Cambridge theft.
Marvin Simos, 16, from east London - who was eventually sentenced with three others for carrying out the Fitzwilliam raid - had been seen checking out Durham Museum hours before the thieves struck. He was seen on CCTV at the time.
Telephone bills allowed police to link several raids in Durham with the Cambridge heist and thefts from Gorringes Auction House in Lewes and Norwich Castle Museum.
The thefts took place between November 2011 and April 2012.
The "pattern of panic" noted after the failed Durham raid was echoed after several other unsuccessful attempts.
When thieves ran off with the wrong item from the Lewes auction house, and were tackled by the public, police noted 26 attempts to contact the gang member who had set up that raid. Those nearer the top of the gang's hierarchy had clearly been desperate to find out what had gone wrong.
"You start analysing the telephones and that ultimately took us to a call to a vehicle insurance company that gave us the details of Richard 'Kerry' O' Brien Jnr," Mr Green said.
"That starts to point towards... [his family, part of an extended traveller family, was already known to police]."
Information cross-referenced with historical data held by Europol "highlighted some potential people - mainly the 'Kerry' O'Briens, Michael Hegarty and Daniel 'Turkey' O'Brien".
All were related and divided their time between Cambridgeshire, Essex and Rathkeale, County Limerick.
At the end of June 2012 the Association of Chief Police Officers, the Home Office and the National Crime Agency were convinced by investigators that "something had to be done about the high-level people" involved.
Sixteen of those who carried out the actual raids had been convicted, "but nobody was taking on the bigger picture".
Operation Griffin was born and Det Supt Adrian Green was asked to head up the team with Det Ch Insp Jim McCrorie from Cambridgeshire Police as his deputy.
How did the team get from a fledgling investigation to the point where 26 forces carried out 40 co-ordinated raids at locations across England and Ireland in September 2013, resulting in dozens of arrests?
"It's just really hard work, in that you've got some names and intelligence and a whole raft of telephone numbers, but you don't know who the users are," Mr Green said.
"Then you put a load of work in to link the telephones to different people.
"They're also to-ing and fro-ing between the European mainland and Ireland - it really is hard graft."
Rhino in car park
Investigators then had to convince a court they had "an overwhelming case" proving certain people had been using certain phones in certain places.
On 10 September 2013 police closed in on numerous addresses, arresting dozens of unsuspecting people.
"They didn't know, until the raids, that Operation Griffin existed," Mr Green said.
All 14 of those sentenced - 12 of whom were from the traveller community - were to be arrested during the raids, but at the time Daniel "Turkey" O'Brien was on the run for GBH after stealing a rhino horn from a man in a car park in Nottingham.
Another had gone on holiday to Europe "and never came back". Daniel Flynn was eventually tracked down and arrested in 2015.
The gang operated on several levels - managers or "generals", lieutenants and sub-lieutenants, Mr Green said.
"At the top you've got your 'Kerry' O'Brien, Hegarty, Turkey O'Brien group.
"The nucleus of this crime group is familial. If they're in the inner sanctum, around family, then they're the main people in terms of recce-ing, planning and commissioning this.
"As a sideline you've got Donald Chi Chong Wong who is obviously the buyer/smuggler facilitator. He's more than just a fence, I would say."
He said he would consider Richard "Kerry" O'Brien Jnr the most senior of the convicted group but added: "I don't think we managed to get the top person.
"I know for a fact we haven't got everyone involved. But I've not charged everybody and I do have leads for other individuals."
Asked about the stolen Fitzwilliam artefacts yet to be recovered, Mr Green said: "We'll always be looking for them but the chances of us recovering all of them is very remote. We might get the odd piece if we're lucky."
Roger Keverne, a Chinese art expert who helped value the museum's stolen jade, agreed the haul was unlikely to be found if it had left the country.
However, the director of the Fitzwilliam Museum remains optimistic.
Tim Knox said: "They're very well-known. They're impossible to sell on the open market.
"I have every confidence that they'll eventually come back to us. They're probably under someone's bed to tell you the truth."