Helping a Foriegn Power, allied or no, is Treason; during a time of war it is sometimes called "High Treason".

Pakistan is fully within its rights to prosecute this man and, frankly, he is fortunate not to be executed.

Having said that - the US should have extracted him, his home country should have given him a trial and the Pakistani's should have nabbed Bin Laden themselves.

So the conclusion to be drawn is that the people who rule the US and Pakistan and particularly their intelligence agencies are jerks but no judge or jury could have let this guy off.