I'm not sure what you can change it to? They can't torture someone to speak. I guess you could adjust the law to be deemed guilty if you don't cooperate in interviews but I'm sure civil liberty groups would be all over it.
The others got away lightly on sentencing I thought. They all knew he was going to murder him so should all have got life. For the shooter it should have been a whole life tariff. He shouldn't even have the chance of coming out ever. It's not like he fired the gun to frighten him and killing him was a mistake, it was a cold blooded execution. Still his life is as good as finished. Go inside as a young ripped 28 year old in his prime, come out at the very least a 64 year old, with all the disadvantages that brings. No collateral, no wife and kids/grandkids, health issues, living on the basic state pension which he probably can't draw until he's 75 by the time he gets out. Nobody will know, fear or respect him, in fact he will probably be a target himself for the next generation of offspring from the likes of him. Personally in cases like this it warrants a death penalty.
All this pain, fear and misery in communities caused by the so called war on drugs. Get them legalised. Just like prohibition in the states with alcohol it just doesn't work making something vast amounts of people enjoy doing illegal, it just creates what we see in these programmes.