What would you do?

You are a federal agent investigating a major drug ring over a long time. One of your informants is highly placed within this ring and has been providing you with good information. You could "turn" him because he faces a murder charge: there is probable cause that he shot and killed a coworker during an argument about five years ago, before he became involved in the drug ring. You have been holding the murder charge over his head to get him to cooperate and have been able, with the help of the U.S. District Attorney's office, to keep the local prosecutor from filing charges and arresting him. The local prosecutor is upset because the family wants some resolution in the case. You believe that the information he can provide you will result in charges of major drug sales and racketeering against several of the top smugglers, putting a dent in the drug trade for your region. At the same time, you understand that you are constantly risking the possibility that he may escape prosecution by leaving the country, and that you are blocking the justice that the family of the murdered victim deserves.

what would you do?