He made a call as serious as possible to get the police to raid the house...that much is known...but you cannot prove that he intended the cops to execute the individual. The fact that a guy got killed is a tragic error in judgement from one police officer. In most of these SWATing cases...no one dies. The intent is just to get another person to shit their pants.
If the prosecutors push for more than involuntary manslaughter...they have to prove, beyond all reasonable doubt, that there was intent to get someone killed. If they can't prove that...he walks.