As the first funerals for the victims of the Pittsburgh massacre began, two rabbis and five other volunteers approached the sawhorses cordoning off the Tree of Life synagogue, and an FBI agent led them into the crime scene. Inside the desecrated temple, the men donned white forensic coveralls, face masks and gloves, and set to work.

Judaism asks the living to take special care of the dead, and this group had a last, sacred duty to fulfill: gather up every drop of blood and other bodily traces of the 11 people killed in the deadliest attack against Jews in U.S. history.

"The Jewish law is that everything that belonged to the body needs to be buried, so we do our best," one of the group's leaders, Rabbi Elisar Admon, said Tuesday.

The work is meticulous and mentally taxing, carried out with implements as ordinary as wipes and paper towels.

Judaism is very specific about death and how it should be handled, whatever the circumstances. When a loved one dies, religious law requires that representatives of the living accompany the body until burial. In a ritual known as tahara, the remains are carefully washed and placed in a white shroud. Jewish law mandates that the burial take place as soon as possible.

But the scale of the violence wreaked by a gunman Saturday has placed an extraordinary responsibility on those dedicated to this work, all volunteers. The victims included one of their own, Jerry Rabinowitz, a doctor who had worked with the group in the past to prepare bodies for burial.

Recovering and preparing a body for burial are traditionally done by the local chapter of the burial society called Chevra Kadisha, led in Pittsburgh by an Orthodox rabbi, Daniel Wasserman. He works alongside Admon, who, as a member of Israel-based Zaka International, spent many years in his home country recovering bodies at the scenes of accidents and terrorist attacks.

All those volunteering earn their living doing other jobs. In addition to Wasserman and Admon, who teaches at a local religious school, the group at the Tree of Life included a doctor, a house painter and a paramedic.

Their work began hours after Saturday's attack. Late that night, the FBI allowed Wasserman and Admon inside the synagogue. The men drew themselves a map, showing the precise spot where each of the victims was killed. Then they spent most of the night accompanying the bodies as they were removed to the medical examiner's office.

"I'll tell you the truth, Saturday night was very tough. I came home and I just started crying," said Admon, choking back tears.

"I've been to a lot of scenes, but these are people you know very well," he said. "It was very hard to see, like, people coming on a Saturday morning to a peaceful place ... to get a connection with God and the same moment they got a connection with God, an evil person came and in and said, 'Guys, just because you're Jewish, I'm going to kill you.'"

The task of recovering remains, he said, is best undertaken with a minimum of thinking, and a focus on the work itself. FBI agents went to great lengths to accommodate the volunteers, bringing additional lighting into the room they were working in on Tuesday and providing safety clothing and other equipment, Admon said.

As the investigation continued all around them, the volunteers finished removing remains from one room Tuesday but will be going back as allowed by the FBI.

Most of the funerals will be over before the volunteers can complete their work. That means that the remnants recovered from the synagogue will probably not be placed in the victims' caskets. They will instead be buried separately at the cemetery, with markers listing the names of the dead.

For the volunteers, it provides the satisfaction of performing a crucial task. In the end, Jewish law will be fulfilled. But just as important, Admon said, recovering all traces of victims and making them whole will "give these people the respect they need, because it's the minimum we can do."