A federal jury in Baltimore has ordered John Eugene Sellner, a former Prince George's County police officer, to pay $1.2 million in damages to two cunty residents for slandering the two men by his charges that they had killed the wife of one of the men and then switched identified to cover up the murder.

Award by the jury, which was made last Tuesday, was the result of a libel suit filed against Sellner two years ago by George A. Hudnall and James P. Panagoulis. Sellner had publichly charged -- through newspaper accunts, widely distributed mockups of wanted posters and contacts with law enforcement officials -- that Panagoulis had murdered Hudnall's wife in 1968 and then switched identifies with George Hudnall to disguise himself and his responsibility for the unsolved murder.

Martha Hudnall was stabbed to death in January 1968 and police have never found her murderer. Panagoulis, the son of former Prince George's County police chief George Panagoulis, has been living in Florida for the last 13 years. Hudnall is remarried and lives in Elkins, W. Va.

Since 1977, Sellner has repeatedly charged that Hudnall is actually Panagoulis and he has contacted friends, neighbors and employers of the two men with his allegations. According to Hudnall's attorney, George Pappas, Sellner has made various attempts to have Hudnall arrested and has sent mockups of a "wanted poster" accusing Hudnall of murder, bigamy and fraud to associates of Hudnall and Panagoulis.

After a 10-day trial, the six-member federal court jury found that Sellner, a perennial candidate for Congress, had slandered both Hudnall and Panagoulis with his charges. The jury awarded $650,000 to Hudnall, whol alleged he suffered serious marital trouble because of Sellner's actions, and awarded $595,000 to Panagoulis, who attempted suicide two years ago, allegedly because of Sellner's charges.

According to testimony presented at the trial, Sellner in 1974 told a former Prince George's County courthouse employe that the allegations were his his way of striking back at the Prince George's police and politicians for forcing him into retirement in 1974.

Sellner could not be reached for comment yesterday.