A suspected killer who has been on the run for two years from UK police has been put on Interpol's worldwide most-wanted list.
Shane O'Brien, 30, is alleged to have murdered 21-year-old Josh Hanson in an unprovoked knife attack in a bar in Hillingdon, west London, in 2015.
After the attack Mr O'Brien possibly went to the Netherlands and United Arab Emirates before returning to Europe.
A £50,000 reward is being offered for information leading to his prosecution.
Mr Hanson's mother Tracey and sister Brooke said their "lives will never be the same without Josh".
"Someone somewhere also knows where O'Brien is and can change the pain and uncertainty that each day brings for us," his mother said.
"We ask you to try and imagine the emptiness that we have been left to live with, please, please, please do the right thing and make that call or encourage someone else to."
Mr O'Brien, originally from Ladbroke Grove, is described as white, 6ft tall, with grey eyes, dark brown hair, a full beard and a tattoo on his back of an owl holding a skull, covering up a previous one of "Shannon 15-04-06".
Police say he is dangerous and should not be approached.
The Met Police say Mr O'Brien was flown out of the UK on a privately-chartered plane from Biggin Hill Airport.
He was arrested in Prague for criminal damage and assault in February 2017 under the Italian alias Enzo Mellonceli and released on bail.
Mr O'Brien has been travelling "extensively" with sightings reported in Gibraltar, Nice in France and Prague.
Det Insp Noel McHugh said: "We are looking to people in nightclubs and boxing gyms as well as expats and any women he may have become involved with to come forward.
"Everyone wants to give Josh's mum Tracey and his sister Brooke the news they so desperately need to hear."
Mr Hanson, from Kingsbury, north-west London, was stabbed in the neck at the RE Bar in the early hours of 11 October 2015 and died from his injuries at the scene.