PANAMA CITY, JAN. 6 -- For most of his life, Alberto Mejia, 56, was a civilian cook for the Panamanian military, first for the National Guard under Gen. Omar Torrijos and later for the Panama Defense Forces under Gen. Manuel Antonio Noriega.

He was cleaning up after cooking a late dinner for Panamanian troops guarding the airport here when U.S. forces attacked it the morning of Dec. 20. Mejia ran for cover and was shot dead by PDF forces behind him, according to his daughter, who cited witnesses.

Assuming her account is accurate, Mejia's death raises a key question: Was he a civilian casualty of the U.S. invasion? Was he a military casualty? Or was he a murder victim?

Mejia's case illustrates some of the difficulty in counting civilian losses here from the U.S. invasion that toppled Noriega. Mejia's daughter Marisa, tearful after identifying a picture of her father's body at the Forensic Registry, said, "The PDF murdered him. They shot him in the back." She does not blame the United States for her father's death.

Critics of President Bush's move in Panama have cited reports of mass graves, incinerated corpses and devastated neighborhoods as evidence of unnecessary and reckless deployment of U.S. military strength. The known dead are not easy to classify, and rumors abound that hundreds, perhaps thousands, of other dead civilians lie unidentified and uncounted in secret places.

U.S. and Panamanian officials say it isn't so. Panamanian officials say they have processed 250 bodies classified as nonmilitary personnel killed since the invasion. They expect more bodies, but not many, to turn up, and say that some of those currently counted as nonmilitary may later be reclassified. The estimate includes dead from all over the country, 40 of them from the Atlantic port of Colon.

"Perhaps 300, all in all," said Roger Montero, director of forensic medicine at the registry and for three years the man responsible for recording all of Panama's dead.

No one says that figure is insignificant, especially in a country of only 2.2 million. In addition, the U.S. military reported 23 U.S. dead, 323 wounded, 314 "enemy" dead and 124 treated at U.S. facilities for battle wounds. An administrator of a displaced persons' center at Balboa High School estimated that about 2,000 people lost their homes.

But human rights officials say it could have been much worse. Panama Civil Rights Committee director Oswaldo Velasquez praised the military action as "a surgical procedure to remove a cancer." His office said no complaints had come in against U.S. soldiers and that the number of worried relatives searching for missing loved ones was "not in contradiction" to official death tolls.

Still, the civilian total remains uncertain. "You can't say the war started at 11 p.m. and ended at 4 a.m.," said the Rev. Reynaldo Caramanitis of Christ the People Church in the slum of San Miguelito. "It was a chain of one thing to another." In that sense, U.S. forces were responsible even for the looters' deaths, he said.

U.S. military officials at first promised and then refused to provide their count and analysis of civilian dead. In an interview with Washington Post reporter George C. Wilson, Gen. Maxwell R. Thurman, chief of the U.S. Southern Command, said there are no accurate figures on civilian wounded.

"I believe press reports have gone way out front in terms of the number of casualties" in the civilian community, Thurman said. "I can't tell you, and neither can the hospital records, whether they are PDF dead; whether they are PDFs in civilian clothes; PDFs in uniforms, 'digbats' {squads of paramilitary Noriega loyalists called Dignity Battalions} in civilian clothes or whatever."

The registry's Montero displayed lists and charts accounting for what he thinks are nearly all the bodies that were not immediately classified as military casualties. "Panamanians have long been accustomed to bringing the dead to civil authorities," he said, adding that even the mass graves are known and counted.

The dead were collected largely by U.S. troops in the first days after the invasion, when snipers and armed Noriega loyalists were still shooting it out with U.S. forces and looters were exchanging fire with each other and with armed, businessmen's vigilante groups.

Maj. John Shirk, chief of logistics in the readiness and resources division of the Southern Command headquarters here, said troops brought bodies starting Dec. 20 to collection points set up initially at Howard Air Force Base, west of Panama City, and at Gorgas military hospital, long the city's largest morgue, near U.S. military headquarters. Shooting around Gorgas forced the opening of a third center at Albrook Field, two miles north, he said.

Civilians, meanwhile, brought bodies and the wounded to the midtown Santo Tomas Hospital, which was almost immediately overwhelmed. Medical supplies were scarce, at least in part because Noriega's forces had stockpiled inventories in their own warehouses, according to U.S. military officials, who seized tons of medical supplies in raids later in the week.

"We had a warehouse in which you could have played football, it was so empty," said Juan Ramirez Harris, a cardiologist at Santo Tomas. In addition, the hospital compound "was filled with armed people who were issuing guns and ammunition," he said. They were Noriega loyalists who had come in with the wounded to take cover.

The Santo Tomas morgue, with a capacity of 14 bodies, was partly filled before the invasion began. Within hours, 83 bodies lay stacked in the halls, Ramirez Harris said. "They were lying on the floors. They weren't even in bags," he said.

Montero said a standard procedure was used to process each body. "We noted small details of each one, like marks or scars, the type of shoes, the things they carried, the color of the clothes, and we took a picture" of each face, he said. The documents were carefully filed, and the color pictures of those carrying no identity documents were posted in a room down the hall from Montero's office. The grisly photos, nearly all of young men, cover about 25 square feet of wall.

The dead and the wounded at all the hospitals and collection points came from all over the city, officials said. "We couldn't always say if a casualty was a PDF, a civilian or what," Shirk said. "If a guy was shot carrying a weapon, that was a pretty good indication he was not a friendly." But troops under fire didn't always have time to label each corpse with the location where it was found, he added.

Pedro Alvarado, director of a funeral home across the street from Santo Tomas, helped out in its morgue during the initial phase. Most of the dead were young men, he said. "Some had new sneakers, they had two or three wristwatches on," he said. "Those would be looters. . . . Some had on camouflage T-shirts, so they might have been PDF" in civilian outer clothing.

He estimated that 30 percent were PDF in civilian clothes or members of the Dignity Battalions, diehard Noriega loyalists shot either during looting or in firefights with U.S. forces.

All the officials agreed that gunshot wounds took the most lives everywhere, although the bullets' sources were usually unknown. Some people were slashed by broken glass, presumably from kicked-in storefronts, and bled to death, hospital officials said.

Amalia Rodriguez French, medical director at Santo Tomas, said that of the 220 dead handled at the facility, 13 died from burns, probably suffered in the fire that ravaged the poor neighborhood of Chorrillo in the wake of a fierce U.S. attack on the PDF command headquarters there.

The cause of that fire, according to the Rev. Javier Arteta, a parish priest, was arson and not U.S. firepower. He said witnesses saw Noriega loyalists set fire to houses there on the morning of Dec. 20. Other witnesses, however, saw tracer bullets fly through the night from both sides, setting fires where they landed, a problem U.S. military officials have acknowledged. But no bullet holes mar buildings next to the command headquarters, and a Christmas creche outside the blasted Balboa police station was intact.

Mario Armando Howard, 36, a janitor, took cover from the violence in a Chorrillo school, but armed gangs of Dignity Battalion members turned their guns on the school. The occupants fled, he said.

Across the city, Caramanitis, the parish priest, was putting up Christmas garlands on his porch in San Miguelito when a blast rattled the windows. U.S. helicopters had begun bombing the Tinajunta hilltop PDF post on one side of his parish and the 11th PDF Military Zone headquarters on the other side. "We had a ringside seat," he said. In the next few days, "after the looting stopped," Caramanitis surveyed 628 homes in his parish and found that 19 people died, 10 were hospitalized and 72 homes were damaged.

"Some {of the casualties} were in their houses when bullets came through the roof. Others were in the streets afterward," shot by storekeepers for looting, while others ignored soldiers' roadblocks and were shot then, he said.

About 30 people are missing, he said, but he knows some were arrested by U.S. troops.

Three days after the invasion, officials at the hospital morgue grew desperate. "Embalming is not the practice here," Shirk said. "It soon got to the point where we had a health hazard."

"We didn't have enough doctors or police or gloves or space or anything," said mortician Alvarado. U.S. officials "asked my professional opinion what to do and I said the best thing would be a common grave."

U.S. refrigeration trucks took 26 unidentified bodies in bags to the Panamanian cemetery at Corozal that weekend and buried them side by side in a large temporary grave dug by bulldozers, Shirk said. One week later they were exhumed and delivered to civil authorities. Another 124 unclaimed corpses were taken to the Panamanian Garden of Peace cemetery and buried there in carefully documented rows, according to cemetery administrator Ramon Soto.

"Given the gravity of what happened here, I think the number of dead was minimal," said Ana Belfont, chief prosecutor for Panama City.