With flames shooting from all directions and neighbors pleading for him to jump three floors below, Hassen K. Beshir, 35, leapt for his life early Sunday from the balcony of his burning Fairfax County condominium. Even as he lay seriously injured on the ground, his pants on fire, witnesses said Beshir pleaded for someone to save his family.

"My mother, my sister, please! I can't wake them," a witness recalled Beshir yelling on the ground.

Beshir was hospitalized and is expected to survive. But his mother, sister and a family friend perished in the fast-moving, intense blaze that destroyed their home in the Victoria Crossings at Manchester Lakes complex. The three-alarm fire caused an estimated $9 million in damage.

The cause of the 5:20 a.m. fire remains under investigation, but officials said yesterday that they do not believe it was related to the 39 fires conclusively or tentatively linked to a serial arsonist in the Washington region since March 2003.

The complex was built in 1988, before county codes required that sprinklers be installed in similar buildings, officials said.

Neighbor Sharon Mack, 38, said yesterday that the situation was so dire and the fire worsening so quickly that she joined other neighbors in yelling for Beshir to jump.

"If he didn't jump, there was no way he was surviving," Mack said.

Beshir's mother, Sadia B. Mohammed, 68, and his sister, Anisa A. Yassin, 36, were killed along with family friend Iftu J. Salah, 16. All three died of carbon-monoxide poisoning from smoke inhalation, said Lt. Mark D. Stone, a county fire department spokesman.

Fire officials said the victims were a family of immigrants from Ethiopia, and neighbors said the community in Northern Virginia has rallied to help them. At a nearby Starbucks, an informal gathering place for local Ethiopians, one woman said she knew the family to be good and hardworking.

Fire officials said 18 of 24 units on Mary Caroline Circle in the Franconia section of the county are uninhabitable. About 48 people were displaced, said Red Cross spokesman Cameron Ballantyne.

Yesterday, about a dozen of the residents gathered two blocks away at the Manchester Lakes Community Center, where fire officials updated them on the condition of their condominiums, and volunteers from nearby Calvary Road Baptist Church offered meals made of food donated by grocery stores.

The Red Cross set up a shelter at the church Sunday but closed it late that night after all displaced residents found lodging with friends or family.

Throughout the day yesterday, residents from other parts of Manchester Lakes stopped by the community center to drop off bags of clothing, towels and toiletries, which officials piled up in a basement exercise room. One day after the fire, most residents had gotten over their shock and were concerned about how to get their lives in order, said George Boals, an administrator for the church.

Investigators from the county fire department and the Bureau of Alcohol, Tobacco, Firearms and Explosives combed over the charred skeleton of what used to be neat, three-story apartment buildings. Fire officials said they are trying to figure out where, when and how the fire erupted. Stone said the size and scope of the damage probably means at least one more day of intensive sifting and testing. It is also not known whether there were working smoke detectors.

Yesterday afternoon, investigators were carefully examining the first-floor rear porch area. Around them was charred detritus of suburban life: patio chairs, a mountain bike, a snow shovel and a soot-covered barbell.

Under a small tent, investigators used little hand tools to carefully sift through a pile of ashes. Every few minutes, firefighters brought another bucket load.

"We're not even at the 'I think' stage of figuring out what happened," Stone said. "Everything tells a story, and we have to check and recheck everything."

Battalion Chief Mike Reilly said investigators are looking for the pattern of how the fire spread in order to trace it back to its origin. The pattern could also tell investigators how the fire started and whether an accelerant was used.

"We're getting close to where the origin of the fire was," he said.

Stone said the department does not believe the fire is related to the serial arsonist, but county fire officials consulted with the task force about the blaze. He said the ATF was participating in the Fairfax investigation merely as extra help, not as part of a probe into weapons or explosives.

Many residents were jarred out of their sleep Sunday morning by neighbors and officials who pounded on their doors and windows, screaming for them to evacuate their homes.

One of the first outside was Preston "Shorty" Penn, who was awoken by a neighbor who spotted flames leaping from the building when he arrived home at 5 a.m. Penn rushed outside to help alert other residents as the flames spread and grew -- from five feet tall to engulfing the building in what seemed like seconds, he said.

"It was the quickest thing I've ever seen," said Penn, 42, a glazier whose apartment sustained only soot damage and is one of the six that is still habitable. "It was a lot of smoke -- it's all vivid, but . . . some of it I want to forget."

Staff researcher Bobbye Pratt contributed to this report.

A sign outside the condominium building in the Franconia section of Fairfax County warns that the area is unsafe and that occupancy is prohibited.Investigators examine the scene of the fast-moving fire in Fairfax that killed three. "We're not even at the 'I think' stage of figuring out what happened," said Lt. Mark D. Stone, a county fire spokesman.