They were at a cemetery far from the couple’s home near San Bernardino, Calif., an attendee told Reuters, because a closer graveyard refused to accept the bodies. They feared that the graves would be desecrated, among other concerns. It took a week to track down a cemetery that would agree to be the final resting place for the terrorists.

This is an unseen aftermath of terror attacks and mass shootings. The slain innocents, appropriately, are interred with honor, tears and candlelight ceremonies. The families and survivors grieve, and the nation grieves with them. It’s little solace for their trauma, their senseless loss. But it’s something.

For the families of those who did the killing, burial is solitary, imbued with horror, shame and fear. Funerals, if they are even held, are expedited affairs. Tombstones are left unmarked by the names inextricably linked to violence. Sometimes families go from funeral home to funeral home, cemetery to cemetery searching for a place willing to offer a gravesite.

After all, a grave is a site for mourning, a place to pay one’s respects. And who mourns a murderer?

“I wished for my son to kill himself, and he did,” Susan Klebold said. Her son was Dylan Klebold, one of two students who killed 13 people in the 1999 massacre at Columbine High School in Colorado. He and his fellow gunman, Eric Harris, committed suicide at the end of their shooting spree.

“While every other mother in Littleton was praying that her child was safe,” Susan Klebold told author Andrew Solomon for his book “Far From the Tree.” “I had to pray that mine would die before he hurt anyone else.”

Dylan Klebold in a 1998 yearbook photo from Columbine High School in Littleton, Colo. (AP Photo)

Rather than bury their Dylan’s remains, the Klebolds had him cremated — a grave that doesn’t exist can’t offend. But they wanted some kind of service for their son, so they phoned Don Marxhausen, a liberal-minded Lutheran pastor from their town. He agreed.

Accompanied by a policeman, the pastor presided over Klebold’s sparsely attended funeral. Those few mourners who came arrived by circuitous routes, to avoid drawing attention to the ceremony.

At the service, Marxhausen told the Old Testament story of Absalom, King David’s rebel son who took part in a revolt and was killed. David mourns Absalom’s death despite his bloody treachery, Marxhausen later told The Washington Post — just as the Klebolds mourned Dylan.

Marxhausen’s role later lost him his job, but he told the Associated Press in 2012 that he didn’t regret it.

“Christ always goes where it’s darkest. You do your job,” he said.

Harris’s family never revealed the site of their son’s burial. His is one of several infamous names that can’t be found in cemeteries, either because families have worked to hide them or because there is nothing to mark their final resting place: Adam Lanza, who killed 26 people, including 20 first-graders, in the attack on Sandy Hook Elementary in Newtown, Conn., in 2012; Seung-Hui Cho, who killed 32 people at Virginia Tech; Timothy McVeigh, the Oklahoma City bomber who was executed in 2001, are all hidden. Before McVeigh’s death, Congress passed a law to ensure that the Gulf War veteran couldn’t be buried in Arlington National Cemetery; he was later cremated, and his ashes were spread at an undisclosed location.

Like McVeigh’s, the gravesite of Tamerlan Tsarnaev, the alleged Boston Marathon bomber who died during a shootout with police shortly after the attack in 2013, was contested. His uncle Ruslan Tsarni had hoped to bury Tsarnaev in Massachusetts, where he lived, but no cemetery would let him, according to the Los Angeles Times. Tsarnaev’s wife refused to claim his body, and his parents would not return to the United States to arrange his funeral.

“I do understand no one wants to associate their names with such evil events,” Tsarni told public radio station WBUR. But, he added, “I’m dealing with logistics. A dead person must be buried.”

According to Muslim tradition, remains cannot be cremated.

As Tsarni cast about for a gravesite for his nephew, protesters thronged outside the funeral home where Tsarnaev’s body was being held. One toted a sign that read, “Do not bury him on U.S. soil.” A driver passing by shouted, “Throw him off a boat like Osama bin Laden.”

Funeral director Peter Stefan, who agreed to prepare Tsarnaev’s burial, said he received angry calls and mail from people who thought it “un-American” to handle funeral services for a killer.

“We take an oath to do this,” Stefan told WBUR. “Can I pick and choose? No. Can I separate the sins from the sinners? No. We are burying a dead body. That’s what we do.”

Tsarnaev’s body now lies in an unmarked grave in Virginia.

“When there is a funeral for the perpetrator, it is private,” James Fox, a mass shooting expert and professor of criminology at Northeastern University, told ABC News in 2012. Families don’t want the attention because they’re often blamed for their relatives’ crimes, and they leave their relatives’ graves unmarked “because the family is afraid the grave will be defaced.”

Sometimes graves are not marked for the opposite reason: Authorities fear they might become a place of worship.

The body of Leon Czolgosz, who shot and killed President William McKinley, was doused in sulfuric acid until it disintegrated. The body of Lincoln’s assassin, John Wilkes Booth, was kept in a storage room and then a warehouse for four years before authorities would allow him to be buried in the family plot. Booth’s funeral was held in the dead of night, the New York Times reported in 1911, and his grave was unmarked — just a mound of dirt among the tombstones. For a half-century barely anyone knew that Booth was buried there, which likely didn’t do much to tamp down the century and a half of speculation that Booth was never really captured.

And then there are the remains of the worst killers in recent memory: the hijackers behind the Sept. 11, 2001, attacks.

For years afterward, forensics experts have toiled in the wreckage of the World Trade Center, the Pentagon and the field in Pennsylvania, hoping to salvage and identify the remains of those killed. The work is “like cataloging hell,” as New York magazine put it.