He won't be released I think, because he is powerful only in the underworld society, but never had a legal position. Formally, he was just a random peasant. If he was a politician, an important lawyer, a chairman of the directors' board of a big company or business alliance of more companies, just anything that gives a position in the legal society, not just in the underworld, then I think he would have gotten house arrest with no problem a long time ago already, no matter how many life sentences he has. Even mafiosi who are not "white-collar" often get released to house arrest. And, to be honest, in my opinion it's inappropriate to call it "arrest" at all, at least how they do it in Italy: no guards under your door, no electronic bracelet that traces your movements, you can even GO OUTSIDE if it's during a specific period of time, like from 17.00 to 19.00 or something like that. When you are in jail, it's not like you can go shopping and then return to prison, so why do they allow this on house arrest? Isn't it supposed to be like jail, with no movement, just in your house instead on a jail cell?

Just to make an example, how ridiculous it is to call this "house arrest": in 2008, the 'ndrangheta boss Silvio Farao was arrested and placed under "house arrest" instead of jail, because his life sentence wasn't yet upheld by the supreme court. So, Farao took a rest for a couple of days and then went on the run again with no problem, since nobody was guarding the door. So why is it called "arrest" at all?

And, to show that it's impossible to send a "white collar" criminal in jail for life: there was the case of Antonino Velio Sprio, just a small-time employee or office worker in the regional administration in Sicily; small-time, but technically white collar and therefore a member of the "high society". What happened with him shows perfectly how much does this status matter, not only for big-time politicians and tycoons: not only did Sprio have a crime record already and was allowed to work there, but he went on a killing spree ordering hit after hit, after one of his colleagues in the administration, Giovanni Bonsignore, tried to have him fired, after discovering another fraud committed by Sprio. Sprio had him killed, then other 4 people at least (don't remember the details; one was a lawyer with whom Sprio had a money problem I think, others I have to re-check). At the end, when the triggermen got arrested and fingered him, not only didn't he go to jail immediately after his first life sentence, it wasn't even considered enough to remove him from his position in the regional administration. Even after he had already THREE life sentences, ALL UPHELD BY THE SUPREME COURT, he was still under "house arrest". Only after a FOURTH life sentence arrived, they finally took him to jail, where he later received a fifth one and died last year I think. So you see: if it takes so much to put in jail even a small-fry character if he is "white collar from the high society with political connections", can you imagine what would happen if it was a mayor, a governor, a minister etc on trial for murder? Even THREE life sentences are not enough for them to send somebody from that social group to jail for murder. White collar criminals often go briefly to jail for corruption or fraud, but nobody ever wants to try them for murder, probably because it would make "bad headlines" for the "high society". Even a minister can be sent to jail for corruption even if it takes big efforts, but to send them there for MURDER, is impossible. Everybody is already used to the known fact that they are thieves and frauds, but the society will never publicly admit to itself that they are often killers too. Imo it's not a question of "to be easier or harder to prove", but it's about losing face too much and setting a dangerous example: if an important white-collar character is jailed for murder for life in a real prison, not for a non-violent financial crime, then everybody can really become equal for the law sooner or later and that's what they don't want.

Sorry for the long post where many things seem off-topic: I am saying all this to show that, in my opinion, if Riina won't manage to get out of jail and will die there, it's only due to the fact that he never had a position in legal society, and NOT because he is a multiple murderer and those judges have respect for justice. If it was somebody with a public history as a "prominent personality, not just in a criminal sense", he would be out in no time under this "house arrest" that shouldn't even be called that imo.