Federal officials in Florida have dismissed drug charges against a former Alexandria resident, clearing the way for him to be brought to Virginia to face a murder charge in connection with the 1984 slaying of prominent pediatrician Robert S. Rixse.

John Kennedy Robinson, 51, who was married to Rixse's ex-wife at the time of the slaying, will not contest his extradition from Florida to Virginia, his attorney, Garland T. Byrd, said yesterday.

Alexandria Commonwealth's Attorney John E. Kloch declined to say when Robinson would be brought to Virginia, but other sources said it could be next week.

"He's quite anxious to go up there and confront these charges," Byrd said from his Butler, Ga., office. Robinson, who is being held in a Florida jail, faces a murder-for-hire charge returned by an Alexandria Circuit Court grand jury in October.

Assistant U.S. Attorney Alan Sprowls filed a request in federal court in Pensacola, Fla., on Monday, asking for dismissal of four drug counts brought against Robinson a year ago. U.S. District Judge Roger Vinson signed an order dismissing the charges Wednesday, court officials there said. Sprowls could not be reached for comment.

Byrd said prosecutors usually request dismissal of charges when they do not have sufficient evidence to proceed to trial. Robinson's trial was to begin Monday.

Robinson, a Macon native, has been held in a Florida county jail since his arrest in August on the drug charges. Alexandria police have filed a detainer on Robinson, seeking to return him to Virginia.

Police had long believed that a hit man killed Rixse, 37, who was shot at the front door of his Kentucky Avenue home in Alexandria on July 1, 1984, as his three daughters slept upstairs.

At the time of his death, Rixse and his ex-wife, Diane, were involved in a bitter court fight over joint property. Rixse had won custody of the children during the couple's 1981 divorce.

After the slaying, Diane and John Robinson and the children moved to Marietta, Ga. The Robinsons divorced in May of this year, after separating last October.

In August, police obtained a copy of an account, allegedly handwritten and signed by Robinson, that purports to lay out how Rixse's slaying was conducted.