For Ann, 59, and Mike, 63, this is the first shred of news in a long time. So frustrated have they found any efforts to get to the bottom of their daughter's disappearance, they have enlisted a private investigation team to aid their search for the truth.
How a young, popular woman can just vanish into thin air while working on a busy, family-friendly cruise liner may seem astonishing.
But Rebecca's case is far from isolated and highlights the serious difficulties in getting help when a crime has been committed at sea.
Since the year 2000, around 200 people have gone missing from cruise ships, but in many of these cases, their families, like Rebecca's, are left in limbo - not knowing if their loved ones are dead or alive, and unable to grieve.
John Halford, 63, also disappeared while on a Red Sea cruise in April 2011. The father-of-three, a bookseller from Milton Keynes, Buckinghamshire, had left his packed suitcase outside his cabin door on the last night of his holiday. He went for a drink at a cocktail bar and was never seen again.
His wife Ruth, 51, who had stayed at home to care for their children, has told of her deep anguish at not knowing John's fate, but she does not believe he committed suicide.
This week, their eldest daughter Lucy, 26, summed up their terrible predicament: 'One day he was here, the next he wasn't. We don't know whether our father is alive or dead.'
The cruise industry is a huge business.
Each year, more than 25 million holidaymakers - two million of whom are British - board liners to enjoy relaxing, sun-soaked holidays where their every need is taken care of. These vessels are behemoths of hospitality, with pools, gourmet restaurants, spas and cinemas.
Many view a cruise as a safer way to travel, free from the hassles of airport security and navigating foreign roads.
But what passengers may not realise, is that as you pass through international waters, you have effectively travelled to a country where there are no police.
In fact, once you sail 12 miles away from the shoreline, you are no longer protected by your own police force, nor by the nearest country to you. Instead, under Maritime Law, any crime committed is the responsibility of whichever nation the vessel has been registered with.
For tax reasons, most ships tend to be registered under 'flags of convenience' in small states such as Panama, Libya or Bermuda. In the case of Liverpool Hope University student Rebecca, the 83,000-tonne Disney Wonder was one of 80 cruise liners registered with the Bahamas.
Many of the police forces from poor countries with questionable human rights records are stretched to the limit when it comes to dealing with their own domestic workload, let alone with a crime which took place at sea thousands of miles away.
For example, if there is theft, rape or even murder committed on board, cabins can be cleaned, evidence disposed of and witnesses disembarked before often under-resourced and ill-equipped officers finally arrive.
And until a person is reported as missing, the ship continues to move away from where the incident occurred, widening the search area until the recovery of any body becomes impossible.
As a case in point, after Rebecca disappeared, a single Bahamian police officer was flown 1,500 miles by a Disney private jet to investigate - just one man to interview the 2,400 passengers and almost 1,000 crew on board the £580 million liner.
The officer, Paul Rolle, did not bring any forensic equipment with him, nor did he interview more than a handful of crew members.
After what can only be described as a cursory investigation at best, he concluded she must have been washed away by a freak wave on the second day of a week-long cruise from LA to the Mexican Riviera - an explanation backed by Disney.
However, for the private British team now investigating Rebecca's disappearance, this explanation simply does not stack up.
Roy Ramm, a retired former Commander of Specialist Operations at Scotland Yard, has compiled a detailed report into Rebecca's case. He also believes that she was the victim of a sexual assault and, after this, she was either pushed overboard by her attacker or was in such a distressed state that she took her own life.
Roy, 66, who spent 27 years working for the Metropolitan Police, is helping the Coriams for free after coming across a news report of the story. He explains: 'I was so moved by Rebecca's case, I wanted to help - to use the skills and knowledge I acquired during my police career.'
'I was aghast by the appalling quality of the investigation. I thought it was awful, there were so many things that didn't look right. To me, it was more about keeping the ship on schedule than finding the truth about Rebecca.'
He points to flaws in the case, such as how none of the insufficient number of interviews Rolle conducted were recorded, nor was any forensic examination carried out on board - including Deck Five where Rebecca, who was in a relationship with a female crew member, allegedly disappeared from.
Oddly, the last CCTV images of her were captured four decks below. She is seen dressed in men's clothes, talking on the phone and looking upset at 2.45am. Mysteriously, her credit card was used two months after her disappearance.
Roy says other failings include how her possessions, such as her laptop and phone, were not taken for examination and there has never been an inquest.
Furthermore, Rebecca's favourite shorts were found to be ripped when they were returned to her parents - indicating a possible violent struggle - and the flip-flops which were said to be hers and found on Deck Five, were the wrong size and had a different name written on their soles.
'I believe it's a cover-up,' he says. 'It's a PR nightmare for Disney and they just wanted it to go away. As one crew member told me, they don't want anything to happen that takes the smile off Mickey's face.
'If someone investigated the burglary of a bike shed during my time in the Met to such a poor standard, I'd have been pretty disappointed.
'The explanation that Rebecca could've been washed overboard is implausible, to say the least. There were no stormy seas reported at the time and a wave would've had to be 100ft high, this would've been felt across the ship, it would've been recorded in the ship's log.'
Additionally, he says there are serious questions to be asked as to why the ship did not turn round to look for Rebecca after she was reported missing on failing to turn up for work at 9am.
When a search was finally carried out almost a day later by Mexican coastguards, he says it was of the wrong section of water.
'The temperature of the sea at that time of year would have meant that anyone who fell into it could have survived for 14 hours.'
Another theory of suicide fails to fit, the Coriams believe, as Rebecca - a super-fit triathlete who had been working as part of the Disney onboard youth activities team for nine months - seemed happy when she spoke to them in the days before she vanished.
She had recently also bought tickets for her parents to visit Disneyland Paris - a sign she was looking forward to the future. The family - denied access to the Bahamian police report - recently visited minister Brandon Lewis to ask for the case to be re-opened and examined by British officers.
Chris Matheson, the family's local MP, also attended this meeting. He says: 'It's clear from Commander Ramm's investigations that the initial investigation was shambolic.
'I have asked the Government to find any way of getting the police involved, to review and investigate the initial inquiry and to assist with a new one.
'It's about time the Government started standing up for British citizens abroad.'
The issue of how British citizens are treated at sea is a point which comes up time and time again whenever there is a crime on international waters.
Of the 200 disappearances, many are written off as accident or suicide but each is recorded by the International Cruise Victims organisation (ICV), a group founded by U.S.-born Kendall Carver.
His own daughter Merrian, 40, who was married to British man and had a teenage daughter in London, disappeared during a seven-day cruise in 2004.
A cabin steward noticed her absence on the second day, but nothing was done about this so when the ship docked, the crew removed Merrian's belongings and donated them to charity. Kendall, 80, a retired insurance executive, searched for years to find answers about what happened to his daughter, to no avail.
In the end, he turned his efforts to improving safety at sea and in getting the FBI to assume jurisdiction for all crimes committed against U.S. citizens at sea, meaning that Americans now have better protection than anyone else in the world.
He says: 'Security on a cruise ship is run by these cruise ships and they are not going to do anything to help some of the crime cases because the cruise ship may then be liable.
'I know of rape cases where the cruise ship takes a report then goes to the person accused directly and it becomes a case of "he said, she said" and nothing happens.
'And in terms of investigations being carried out by the flag states, it's a joke.'
Maritime safety expert Captain Michael Lloyd, the British vice- president of ICV, agrees.
'The flag states are to blame,' he explains, 'particularly the small island states where most of these ships are registered and who depend on this money. The number of people who disappear at sea is of considerable concern, particularly when most cases are declared as an accident or suicide, with little or no investigation.'
He says that most passengers are unaware of the risks involved in going on a cruise. 'They do not know that once their ship sails out of Southampton, they are on the high seas and completely under the care of the Bahamas.
'It is no good turning to the security on board as they have the same powers as a bouncer on the doors of a nightclub. While some are ex-police, others have no experience in investigation or treatment of victims.
'The captain and executive officers have no criminal training either and none of them has any legal right to question witnesses or take statements. That has to wait for the Bahamian police and, as many victims have found out, they will wait a long time.'
He adds: 'It is quite inexplicable that a floating city of up to 8,000 people can continue with no law enforcement or trained personnel who have the flag state legal authority to investigate and arrest and until this is done, more passengers will suffer.'
So what can be done to help prevent cases like Rebecca's? Capt Lloyd says Britons should have the same protections as U.S. citizens - British police should investigate - and that man-overboard detection systems should be installed as a matter of urgency.
Rebecca's parents and their daughter Rachael, 26, are prevented from speaking about her case after agreeing a settlement with Disney in 2015, which has not responded to the new allegations.
But in an interview at the time, Mike, who is a gardener, summed up their anguish: 'We don't know if Rebecca is dead or alive. One thing we have always said is there is no way she just went overboard of her own free will.'
Today, thanks to their tireless efforts, the truth is slowly starting to emerge, but, for now, all the Coriams can do is hope that one day they will finally learn the fate of their darling Rebecca.
