Fifteen potential sightings have been made of a suspected killer since he was placed on Interpol’s worldwide most-wanted list, according to police.
Shane O’Brien, 30, is the chief suspect in connection with the murder of Josh Hanson who was stabbed in the neck at RE bar in Hillingdon, London, in 2015.
Scotland Yard said detectives were focusing on possible sightings of Mr O’Brien in Marbella, Bangkok and Dubai.
A £50,000 reward is on offer for information leading to his prosecution.
Mr O’Brien was added to Interpol’s most-wanted list a month ago, having previously been named as one of Europe’s most-wanted criminals.
He has a distinctive tattoo of an owl holding a skull on his back.
Investigators said four of the reported sightings have been investigated and eliminated “but work continues on the rest”.
“I believe we are making it more and more difficult for those supporting and helping O’Brien to remain hidden,” Det Ch Insp Noel McHugh said.
Mr Hanson, from Kingsbury, north-west London, was found with a wound to the neck at the RE Bar, in north-west London, at about 01:10 BST on 11 October 2015 and pronounced dead at the scene.
His mum and sister, Tracey and Brooke Hanson, said they were finding it “harder to cope without justice for him”.
“We are asking the public to help us to get justice for Josh… so that we can grieve for him in peace.”
The Met Police say Mr O’Brien, originally from Ladbroke Grove, west London, was flown out of the UK on a privately-chartered plane from Biggin Hill Airport following Mr Hanson’s death.
He was arrested in Prague for criminal damage and assault in February 2017 but used an Italian alias Enzo Mellonceli and was released on bail.
Mr O’Brien has been travelling “extensively” with sightings reported in Gibraltar, Nice in France and Prague, the Met added.