A Franconia man was in critical condition yesterday from burns suffered during an argument with another man Thursday evening, Fairfax County police said.

Police declined to identify either man and released few details about the incident. They said it appears to be a case of foul play and remains under investigation.

Neighbors and hospital officials identified the critically injured man as Christian B. Hughes, 56, of the 4300 block of Upland Drive. He suffered burns over half of his body and was being treated yesterday at the Washington Hospital Center burn unit.

The other man also suffered burns and was being treated at the same hospital. He was listed in serious condition.

Police said the incident occurred about 5 p.m. Thursday inside Hughes's home.

Paramedics loaded Hughes into an ambulance and drove him to a nearby school, where a police helicopter then flew him to the burn unit.

The other man was admitted to the hospital sometime later Thursday.

Hughes purchased the ranch-style house, in a heavily wooded neighborhood between Franconia Road and the Capital Beltway, in 1980, according to county real estate records.

Hughes was married about three years ago, according to a friend and neighbor, John E. Lynch, but his wife was not at home when the incident occurred.

Lynch said Hughes was retired from the Air Force Reserves and worked for the Air Force in research and development. Air Force officials were unable to confirm that yesterday.

"It's just a tragedy," Lynch said. He said he and Hughes often went fishing together, particularly along the Potomac River in the spring.

The two men also spent time doing yardwork together on their adjacent properties, and they watched each other's houses when one went on vacation, Lynch said. "He's a good solid citizen," Lynch said of Hughes. "This is as good a friendship as they come."