While outrageous, to suspend his pay would be a form of punishment and you cannot be punished twice for the same infraction. What they can do is when he is found guilty fine him the equivalent of his pay for the past 3 1/2 years.
One may be punished for a crime and have to pay a civil penalty for the same offense. Hudson v. United States, 522 US 93 (1997) http://supreme.justia.com/cases/federal/us/522/93/case.html. Could there not be some kind of civil proceeding to suspend his pay?
bring a civil suit against him first to collect the money.
And you can convict for the civil offense before the criminal trial, happens to drunk drivers who do not blow all the time.