They were actually all acquitted by a lower court years ago and the prosecutor had to appeal to get a guilty verdict this year.
I believe there was some technicality that made proving intent difficult - the original contract was vague enough that the defence could argue that killing was never the plan and they only wanted to intimidate the victim enough to drive him out of town, and somehow the message got distorted down the chain of outsourcing to become a hit which was never carried out anyway.
I think that would still count as just conspiracy to commit murder. Not a good thing to do by any means, but not everyone follows through on their plans, so it's a lesser crime.
An attempt likely requires an actual failed attack against the target. It's much more severe.
EDIT: On second thought, I can see how you could consider hiring a hitman as an attempted attack, since once you have agreed upon the hit, the "weapon" has in effect been "fired".