The man police are hunting in connection with the murder of murder of Josh Hanson has made Britain's most wanted fugitives list and could be hiding in the Netherlands.
Detectives urgently need to trace Shane O'Brien, 27, of Ladbroke Grove with a £10,000 reward available for information leading to his arrest and prosecution.
O'Brien has been added to the list by Crimestoppers and the National Crime Agency under Operation Return, a campaign with the full co-operation of the Dutch authorities to track down people believed to be hiding in the Netherlands.
Detective Chief Inspector Noel McHugh, from the Met's Homicide and Major Crime Command, said: "We believe O'Brien could be in the Netherlands, although our enquiries continue in several other European countries at this stage.
"There is a European Arrest Warrant out for O'Brien and we hope the launch of this new Crimestoppers and NCA appeal will raise awareness and lead to his prompt arrest."
O'Brien will also be featured on the Dutch version of Crimewatch on Tuesday (March 8).
21-year-old Josh from Kingsbury , Brent, died after a unprovoked and violent incident at the RE Bar in Field End Road, Eastcote , at around 1.10am on October 11 2015.
Officers and the London Ambulance Service attended and Josh was found suffering a serious wound to the neck. He was pronounced dead at the scene.
A post-mortem examination gave cause of death as haemorrhage, inhalation of blood and an incised wound to the neck.
Since the tragic death of Josh, his mother, Tracey, has put out emotional pleas to catch her son's killer.
His family have since raised thousands to set up a Justice for Josh Hanson charity against knife crime and recently marked Josh's would-be 22nd with a group skydive .
Most wanted: Shane O'Brien
O'Brien is described as a white man, 6ft with grey eyes and short dark brown hair. He has a tattoo on his back saying 'Shannon 15-04-06' and may use the name Troy O'Brien.
He should not be approached by members of the public. Any sightings of him should be reported to police immediately on 999.
Two men have been arrested as part of the investigation.
On October 28 2015, detectives arrested a 24-year-old man and a 29-year-old man - who were on an inbound flight to the UK - on suspicion of perverting the course of justice and assisting an offender.
Both were taken to a London police station and bailed pending further enquiries and are next due to return on a date in late March.
Anyone with information about the murder or O'Brien's whereabouts is urged to call the incident room on 020 8785 8099 or Crimestoppers anonymously on 0800 555111 or via the Crimestopper website .