A Fairfax County psychiatrist remained in critical condition yesterday from injuries received when a mailed package exploded in his hands, and investigators said they had no suspects or motives in the case.

Investigators yesterday combed the charred and damaged office of Paul J. Peckar, in the 2600 block of Sherwood Hall Lane, east of Route 1. About 4 p.m. yesterday, postal inspectors completed the tedious task of collecting evidence, nearly filling a U.S. mail truck with potential pieces to the puzzle.

Other investigators have been interviewing family members, friends and colleagues in search of a motive in the bombing, which occurred about 1 p.m. Friday in Peckar's third-floor office, said postal inspector D.J. Turner.

U.S. Attorney Henry E. Hudson said that Peckar's records were being reviewed, but in a way that protects patients' privacy.

"We have devised a mechanism that provides the most possible protection of the physician-client relationship while allowing us to proceed with the investigation," Hudson said.

Hudson said no specific federal statute regulates privacy issues relating to the case. "It's a careful exercise in the use of legal principles, ethics and common sense," he said.

"It's such a sensitive area," Turner said. He said possible steps for gaining access to the files include obtaining a court order, having another doctor review them or seeking permission from Peckar.

Postal inspectors yesterday afternoon had not been allowed to talk to Peckar, 50, of the 8400 block of Riverside Road in the Mount Vernon area.

Peckar, who suffered severe burns over 30 percent of his body when his clothes caught fire, underwent surgery Friday for blast injuries. He was being treated yesterday in Washington Hospital Center's burn unit.

Investigators have found some clues, officials said.

Jack Killorin, spokesman for the Bureau of Alcohol, Tobacco and Firearms, said agents were able to gather a great deal of evidence from the scene, including a return address on the package. "There was a return address in Washington on the box, and that is being pursued," Killorin said. He would not reveal the address.

The device used was a pipe bomb made of components available at any hardware store, Turner said. It has not been determined what kind of explosives were used, he said. Killorin said the pipe bomb was different from the type used in the Dec. 22 blast that injured Circuit Court Judge John P. Corderman in Hagerstown, Md., leading law enforcement officials to believe that the cases are not related.

The box, which Turner said was "blown apart pretty good," was addressed to Peckar.

Yesterday afternoon, Peckar's wife, Pamela, escorted by family members and friends, was taken to the office to collect some belongings and business papers. "It is total devastation in that office," said Gerald Hyland, a friend of the family and Fairfax County supervisor for the Mount Vernon district. "It's a miracle Paul's alive."

When investigators finished collecting evidence, Turner gave The Washington Post a tour of the damage. The door to office 305, which says Paul J. Peckar, M.D. Psychiatrist, was bowed into the hallway about 10 inches. An ivory couch, which had been moved into the hallway, had what looked like a basketball-sized burn in a back cushion.

"I think it {the box} was opened somewhere in this area," said Turner, pointing to a spot next to a shattered window and below the charred ceiling. The suite next door was visible through a caved-in wall in Peckar's office.

Wires dangled and wallpaper flapped. The waiting area, separated from Peckar's office by a tiny room, looked more like it had been damaged by wind from a tornado. Leaves on the ficus plant were brittle.

Hyland said Pamela Peckar saw her husband yesterday at the hospital, but Peckar could not speak to her. "He was able to respond and acknowledge her presence," Hyland said.

"Outrage is a classic understatement of how everyone feels," Hyland said. He described his former neighbor as "an outgoing, gregarious, fun-loving guy."

George Forschler, the medical center's property manager, said the building would be open on Monday, although some sections of the third floor may remain closed.