Detectives hunting for fugitive Shane O'Brien believe that one of the people helping him hide may soon turn him in because increased pressure thanks to public appeals could make him a 'liability'.
O'Brien, police say, is now on Interpol's gobal most wanted list, due to being the prime suspect in the murder of Josh Hanson, a 21-year-old from Kingsbury who died after he was stabbed in the neck in a bar in Eastcote.
An appeal to find O'Brien was due to feature on BBC1's Crimewatch Roadshow on Monday (June 18). There is already a £50,000 reward for information that leads to his conviction.
Both men had been partying at the RE:bar in Field End Road, on the night of October 11, 2015, when Josh was stabbed. He died at the scene with a post-mortem showing his cause of death as haemorrhage, inhalation of blood and an incised wound to the neck.
Immediately after the incident, Shane O'Brien was smuggled out of the country in a private plane from Biggin Hill airport. For the last two and a half years, police have been searching for the murder suspect.
Originally from Ladbroke Grove, O'Brien was suspected to be in The Netherlands, and later in Dubai. O'Brien was arrested and bailed in Prague on suspicion of criminal damage and assault in February 2017, while using the moniker Enzo Mellonceli, supported by fake Italian documents.
Since then there have been reported sightings of him in Prague as late as September 2017 and police believe he was in the Czech capital for around seven months before moving on. They are now focusing in on Marbella in Spain, Bangkok in Thailand and Dubai.
Four of the 15 reported sightings have been ruled out, but police are confident in the strength of their intelligence.
Detective Chief Inspector Noel McHugh, from the Homicide and Major Crime Command, said: "We are really pleased with the response to our appeals since O'Brien was placed on Interpol's list and would urge people to keep their eyes open wherever they are in the world.
"Please don't be discouraged by the fact some potential sightings have been investigated and discounted - we want to hear from anyone and everyone who thinks they see O'Brien or has any information no matter how small.
"We would encourage everyone to save the 'wanted' poster to their phones so they have all the information they need, and importantly if you are abroad and think you see O'Brien tell local police or call the National Crime Agency's public line on 0370 496 7622, which is staffed 24 hours a day, immediately - it is really important we are able to act quickly."
Police have carried out extensive enquiries in Prague about O'Brien's lifestyle while he was in the city. He was also reported to have been in Gibraltar during the same time frame, and may have been in Nice in November. Police are also investigating reported sightings in Bari, Italy.
DCI McHugh said: "Were these sightings of Shane O'Brien? We know he has been travelling extensively since Josh's murder and has the ability to move around without using his own identity with the help of others.
"Based on what we know about O'Brien's lifestyle and interests, we are looking to people in nightclubs and boxing gyms as well as ex-pats and any women he may have become involved with to come forward.
"Those who have been in close proximity to him may well have seen his distinctive and rather poor quality cover-up tattoo of a owl holding a skull. As always, any calls we receive with information will be dealt with in the utmost confidence."
DCI McHugh goes on to say that with increasing publicity around the world, it is becoming harder for whoever is harbouring O'Brien to continue to do so, and that they may even be the ones to make "that anonymous call".
"After more than two-and-a-half years, some may feel that will we never catch O'Brien," he continues.
"But with the work that has and continues to be done, I believe we are making it more and more difficult for those supporting and helping O'Brien to remain hidden and there will come a point where they will see him as a liability and they will make that anonymous call.
"It is hugely significant that he is now included on Interpol's world-wide Most Wanted list, we now have a global appeal, it is about reducing O'Brien's options."
O'Brien has been described as white, around 6ft tall with brown hair and grey eyes. He previously had a tattoo reading "Shannon 15-04-06" but he has since had that covered up with an owl clutching a skull. He has also grown his hair and beard.
Two men, aged 24 and 29, were arrested in October 2016 on an inbound flight to the UK, on suspicion of perverting the course of justice and assisting an offender. They were both later released with no further action.
Tracey and Brooke Hanson, Josh's mum and sister, said: "Josh has not been a part of our lives now for two years and eight months and every day it is getting harder to cope without justice for him.
"Josh was just 21 years of age and at the prime of his life. We are asking the public to help us to get justice for Josh by sharing the wanted poster, so that we can grieve for him in peace."
Anyone with information about O'Brien or his whereabouts can call Crimestoppers anonymously on 0800 555 111 or visit crimestoppers-uk.org , the police incident room on 020 8785 8099 or the National Crime Agency's public line on 0370 496 7622, which is staffed 24 hours a day.