Today Billy, 56, revealed that
police are closer to unravelling the mystery of his death than they have been since he was slain on his own doorstep in Glasgow's West End 12 years ago on June 24, 2002.
Speaking exclusively to the Evening Times, he said: "I am confident Alex's killer will see the inside of a jail cell.
"The police attitude recently has been spot on and they are making good progress.
"I have been working behind the scenes with them and I have been impressed by the seniority of the officers involved and how seriously they are taking this case.
"They have made a clear commitment to my mother.
"I've had several meetings with senior officers and I know the case is far from dead.
"I can say that there has been quite an increase in police activity recently.
"Over the past 12 years there have been lots of peaks and troughs but I now feel that we are getting somewhere and closer than we have ever been since Alex was murdered.
"The increase in activity is a message from the police that it's not going away.
"They seem to be making it a priority and I feel optimistic that we will see Alex's killer behind bars."
Billy has fought tirelessly to bring his brother's killer to justice and has even given a name of the man he is convinced ordered the execution to the police and Procurator Fiscal.
He added: "I am aware of who ordered Alex's murder and I have given a full report to the Procurator Fiscal and the police.
"The police have responded very positively but what they've said is that it is a very wide-ranging inquiry.
"We have made it very clear to the Fiscal and police who we believe ordered the killing.
"I have a further meeting with police very soon and the police are making progress."
Just hours before he was beaten, stabbed and left for dead outside his front door, Mr Blue was last seen sipping a cappuccino alone at the Beanscene cafe in Cresswell Lane, as he pored over business papers between 7pm and 8pm.
He was found in a pool of blood outside his home at 12.20am on June 25 but he died two days later from horrific head and facial injuries at the Southern General Hospital.
Police launched a nationwide campaign and Mr Blue's family and friends offering a £25,000 reward but his murder was met with a Mafia-style wall of silence.
Up to 30 officers were assigned to the investigation, led by the now retired Detective Chief Inspector David Swindle but the case remains unsolved.
Mr Swindle said: "Someone definitely knows who killed Alex Blue. I have always been confident that with the passage of time allegiances and friendships of those who must know something about this case will change and may result in vital information being revealed.
"As has been seen in some recent historical cases the passage of time is not a barrier to detection, the advances in technology and investigation techniques will eventually identify who was responsible for this murder 12 years ago"
They quizzed more than 5000 people including underworld figures and leading businessmen but with no results.
Detectives even used a private forensic accountant for the first time in Scottish police history to examine Mr Blue's finances in the hunt for clues.
Officers also investigated the possibility that Mr Blue was the victim of a property sting and put out
numerous public appeals.
STRATHCLYDE Police also released an e-fit of a man seen some days before the murder coming out of Mr Blue's flat in Dundonald Road, Dowanhill.
Assistant Chief Constable Ruaraidh Nicolson - Specialist Crime Division, said: "As we approach the 12th anniversary or the brutal murder of Alexander Blue, we can fully understand the pain that his family must be feeling at another year passing without the case being resolved.
"We are acutely aware that no one has yet been brought to justice for this murder despite vigorous investigation and review, using the latest technologies.
"We are in regular contact with Billy and Kathy and they know that they have our absolute commitment to keep working on this case until we can bring the killer or killers to justice.
"It is my sincere hope that by keeping this murder in the public view someone will recognise this family's grief and step forward with the vital information we need."
As well as various other interests, Mr Blue and business partner Greg King, a lawyer and cousin of Stefan King, who owns a chain of city nightclubs and bars, ran the hugely successful Taxi Centre in Queensborough Gardens, Glasgow, which supplied private cars to the taxi trade.