A defendant has a prescription for a drug. He makes a deal with a CI to sell him the drug. He meets the CI later. The CI puts a tv in the defendant's vehicle as payment for the drugs. Before the defendant gets the drugs out of his vehicle and gives them to the CI, the cops bust him for possession with intent to deliver. Would it only be attempted delivery as he had a prescription so you couldn't prove an element of the possession portion of possession with intent to deliver? did that last sentence make any sense at all?

You would hAve to burn your CI but he is already toast since he is now a witness to the arrest and soon to be discovered by the Defense. Let The CI testify and hopefully you have some corroborating surveillance or perhaps an audio recording of the deal they made.