Before critical burns consumed and ultimately killed Christian B. Hughes outside his Franconia home last week, he allegedly told a Fairfax County police call-taker who had set him on fire: his brother-in-law.

Yesterday, Fairfax police charged Hughes's brother-in-law, Issa E. Mansour, 61, of Adelphi, with murder. Mansour was not formally arrested, because he too was burned during the Nov. 11 incident at Hughes's home on Upland Drive. Mansour was still in the burn unit last night at Washington Hospital Center. His injuries were not considered life-threatening, officials said.

Hughes, 56, who worked as a civilian Air Force employee in research and development, was home alone when Mansour, 61, allegedly stopped by about 5 p.m. on Veterans Day. According to a police affidavit filed yesterday, Hughes called 911 "and reported his wife's brother-in-law threw gasoline on him and set him on fire at his home."

Hughes also told the call-taker that the brother-in-law was leaving the area in an older station wagon. When firefighters arrived, according to the affidavit, Hughes told them, "Issa did this."

Two hours later, Prince George's firefighters were called to Mansour's house after he reported that he had been burned in Northern Virginia, the affidavit said. He was taken to the same burn unit as Hughes, who was in critical condition and no longer able to speak.

Detectives later interviewed the wives of both men and learned that the wives are sisters and that Issa Mansour was estranged from his wife. Hughes's wife, Elena Hughes, told police that Issa Mansour had threatened her and Hughes "if they [did] not let him talk to his wife," the police affidavit stated. But police said they were not sure what precipitated the fatal episode.

After Mansour was taken to the hospital, his station wagon was still parked in front of his house, and detectives could smell gasoline and see a gas container inside, police said. Police towed the car to Fairfax and searched it the next day. They found a butcher knife, a half-gallon gasoline can and what appeared to be burned human skin in the driver's seat, according to the search warrant.

Hughes died Saturday morning. He had lived in the Franconia neighborhood for nearly 20 years and married three years ago. Neighbors said he was a friendly man who liked to fish and work around the house, which he apparently was doing when he allegedly encountered Mansour.