An on-the-job squabble between two security guards over promotions at a U.S. Food and Drug Administration office ended in death early yesterday, with one man fatally shot, according to U.S. Park Police.

James Coffman, 33, of the 4600 block of Quimby Avenue in Beltsville, was found by police with a gunshot wound to his head just after 2 a.m. at the FDA's agricultural research facility in Beltsville. He died at 12:35 p.m. yesterday at Prince George's Hospital Center.

Fellow employee Todd McNeil, 33, of Elkridge, was arrested and charged with murder. He was being held at the Prince George's County Detention Center in Upper Marlboro without bond. He is to go before a federal magistrate in U.S. District Court in Greenbelt this morning. Police arrested McNeil on the scene.

The shooting allegedly occurred after McNeil complained to Coffman, his supervisor, about his job assignment. Coffman recently had been promoted while McNeil had not, investigators said.

"It was a 'Why the hell didn't I get promoted?' sort of argument," a police investigator said.

Several other guards on the night shift saw the shooting in the atrium of the FDA building and called police.

Both men were employed by Unlimited Security, based in the District, and were under contract to the FDA. They were permitted to carry firearms on the job, Park Police said. McNeil faces a federal murder charge because the shooting occurred on U.S. government property.

The Coffman family issued a statement yesterday saying: "Our family is deeply grieved by the sudden loss of James, who was a wonderful husband and father. He has been taken from us suddenly and because of that, we need time to fully grasp what has occurred."

Coffman is survived by his wife, Debra, and son, Ian. An education fund is being set up for his son.