THE tattoo on the muscular back of Shane O'Brien can't be missed. A brightly coloured owl, with piercing eyes, its wings spread as it holds a skull with a toothy grin isn't something that's easily forgotten.
But it's what can't be seen - and the reason it has been so cleverly concealed - is what is occupying the minds of some of the world's best police officers.
O'Brien, 30, is one of the world's most wanted men. He was recently placed on Interpol's worldwide most wanted list after being named as a suspect in a brutal stabbing attack in west London in 2015.
He has since gone to incredible lengths to stay hidden, including covering his back with the skull and owl tattoo. Before he became a fugitive the tattoo on his back said Shannon 15-04-06 - but it has now been completely covered over by the skull and owl.
The stabbing victim, Josh Hanson, 21, was outside a bar with his girlfriend when he was allegedly attacked by O'Brien. He was stabbed in the neck and died at the scene. After the attack O'Brien managed to leave the United Kingdom on a private plane - and police have been hot on his trail ever since.
It's believed he was in Holland before flying to the United Arab Emirates and then returning to Europe, although his exact movements are something of a mystery. What is clear is where he was in February last year which is when police got the closest they'd been to catching him.
O'Brien was arrested in the Czech Republic's capital of Prague for criminal damage and assault. The problem is he was arrested under a fake Italian name, Enzo Mellonceli, and was released on bail.
He wasted no time in taking advantage of his second lucky break and once again vanished. By the time police discovered who in fact he was, he was gone.
Since then police across Europe have intensified their efforts to catch O'Brien after sightings of the fugitive were reported in Prague, Nice and Gibraltar when police launched a renewed public appeal.
Now the trail has run cold, O'Brien has joined the list of Interpol's most wanted. The officer leading the hunt hopes it will be enough to finally make an arrest.
As well as the massive new tattoo, O'Brien was last seen with a beard and shoulder length hair.
Detective Chief Inspector Noel McHugh told the Evening Standard they were paying close attention to his known haunts like gyms, boxing clubs and nightclubs. He made a special point of appealing to any lovers O'Brien had.
"We are looking to ... any women he may have been involved with [O'Brien] to come forward," he said.
There was something about O'Brien that made him stand out in a crowd.
"Obviously he will not be travelling under his own name but O'Brien has an air about him, a presence he will struggle to conceal."
One of the biggest clues was the tattoo.
"Those who have been in proximity to him may well have seen his distinctive and rather poor quality cover-up tattoo of an owl holding a skull," Insp McHugh said.
He urged plane and chopper pilots to "keep their eyes and ears open", but also thought there were people helping O'Brien to hide.
"There will come a point where they will see him as a liability and make that anonymous call," Insp McHugh said.
A £50,000 ($AU87,500) reward has been offered for information leading to his arrest and conviction. People have been warned not to approach him if they see him as he is considered dangerous.
Mr Hanson's mum Tracey and sister Brooke said in a statement they had been in a "living nightmare" and they would "never be the same again".
Tracy saw her son Josh the night before he died when they shared a large chocolate desert.
Since he was killed, she has had to give up her job because of post-traumatic stress disorder which left her overwhelmed with panic and anxiety. But she has set up the The Josh Hanson Charitable Trust which aims to help steer young people away from crime by providing knife crime awareness and activities. It has already raised £40,000 ($AU70,000).
The one thing keeping the family going was the hope that an arrest would soon be made in relation to Mr Hanson's brutal death.
"Brooke and I count down the days, hours and minutes hoping and praying that we receive a call to tell us that [someone] has been arrested, so that we can grieve and mourn Josh in peace," his devastated mother added.