The first burials of victims of the attack on the Tree of Life synagogue in the Squirrel Hill neighborhood of Pittsburgh has been scheduled for Tuesday, those close to the victims said.

Other families were waiting for the investigation to continue before they could quickly bury their loved ones, as required by Jewish tradition.

Brothers David and Cecil Rosenthal will be buried Tuesday by Ralph Schugar chapel, Pittsburgh’s Jewish funeral home, Emeritus Rabbi Alvin Berkun told USA TODAY. They were two of the 11 congregants who were killed Saturday when suspected gunman Robert Bowers burst into the sanctuary and yelled "All Jews must die," as he began shooting.

U.S. Attorney Scott Brady said Sunday federal prosecutors were seeking approval to pursue the death penalty against Bowers. Brady said he asked Attorney General Jeff Sessions’ for his approval, as demanded by law to pursue a capital case.

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The attack and subsequent gun battle between Bowers and police was so violent that the synagogue's "breathtakingly beautiful" 1952 chapel will have to be gutted because of the thousands of bullet holes in its walls, Berkun said.

Bowers was wounded as police stormed the building. He was later taken into custody.

All of the victims were still waiting Sunday night to be laid to rest. While some of the bodies of those who died in the attack were released to their families, others were being studied by the medical examiners office.

Melvin Wax’s family will meet with the funeral home Monday, said family friend Bill Cartiff. The funeral will probably take place Tuesday or Wednesday.

“Because the funeral home couldn’t meet with us until tomorrow, we’re kind of in limbo,” Cartiff told USA TODAY. “Everything will happen once the funeral ... and then we set shiva for a few days. That’s when everyone will come be with him for visitation and support.”

Shiva is the formal mourning period observed by Jews after the death of a close relative. Asked why the Wax family has to wait to meet with the funeral home Monday, Cartiff explained, “There’s been a little bit of a backlog. Most of the Jewish families in our area go to the same funeral home.”

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Jewish tradition mandates great care be taken of both the family of those who have died and of the body, said Rabbi Daniel Wasserman with the Chevra Kadisha, or burial society, of Pittsburgh’s Orthodox Jewish community. He was part of a group of volunteers who began waiting at the synagogue Saturday night for the moment when the bodies were to be moved. Jewish tradition requires that bodies be properly respected, accompanied and buried quickly, a difficult task in the midst of a major crime investigation involving 11 deaths and autopsies.

“I had 25 members of our burial society at 1 a.m. last night in the pouring rain standing outside the synagogue in case the FBI and the medical examiner allowed us in to be part of dealing with the deceased,” Wasserman said.

At 5 a.m. Sunday, they assisted as the bodies were removed from the synagogue and brought to the medical examiner’s office.

Because of the large number of people involved and the horrific circumstances of their deaths, burial societies from Jewish congregations across the nation have been offering their assistance and services to the Pittsburgh congregations, Wasserman said.

During a news conference on Sunday, Dr. Karl Williams, chief medical examiner for Allegheny County, said autopsies had begun but did not say how long he expected his office would take to complete them.

In general, Jewish law prohibits disfigurement of the body. Exceptions can be made in the case of autopsies, especially in conjunction with murders where law enforcement needs information that can come from crime scene investigation and autopsies.

That does not mean the bodies of those who were killed at the synagogue will not be respected, said Wasserman. Community members will accompany the bodies in the tradition of k'vod hamet, or honoring the dead. This is something that is done for all members of the community, he noted.

In Pittsburgh, as the medical examiner finishes his work and the bodies are released to the families, they will in turn work with local funeral homes and with the Chevra Kadisha, or burial society, of their congregation, to arrange for burials. Jewish tradition does not allow cremation.

In the case of one of the three congregations that has its home at the synagogue, that work will be especially difficult. One of the key members of the burial society of the Dor Hadash congregation, a progressive Reconstructionist Jewish community, was Dan Leger, who was wounded in the attack, Wasserman said.

The requirement for a quick burial comes from Jewish teachings about the body and the soul.

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"This process helps to remind us that we are only burying the temporary human body. It had a purpose, to be the vessel through which the spirit and soul could act on this Earth. Once the soul and the body are separated by death, it is our responsibility to commit the body back to Earth quickly, as Scripture says,” he said.

While this would be the case for any person, in the case of those who died at the Tree of Life synagogue, the weight of that responsibility is stronger still.

"When a person is killed, solely and only because they were Jewish, then they’re considered a holy martyr, and then the stakes are even higher. In this case, they, in essence, are representing the entire Jewish people, they were killed because they were Jewish,” he said.