Verisimilitude means "true to life," and it's a quality that enhances any story, those of horror included, as it helps in the suspension of disbelief if a fantastic tale is believable in its mundane circumstances. Therefore, should an author of such fiction assay to write a story about grave robbers, he or she ought to be familiar with the extraction methods of such ghouls.
Resurrectionists, as they were known in merry old England. supplied the vast majority of the corpses that medical schools needed for their anatomy courses, the dissection of dead bodies being outlawed except when capital punishment furnished the bodies. There were never enough executions, so the schools were in a constant need of fresh corpses. Body snatchers supplied this need. They used two methods to do so.
In one, a small opening was created, above the coffin. A manhole-size opening was then made in the casket, a rope was secured around the corpse, and the body was pulled free of the grave.
Since family members often mounted a watch upon the graves of their dearly departed and placed various obstacles in their way, such as criss-crossed iron bars, the resurrectionists adopted the strategy of opening the earth some distance from the targeted corpse, dug a narrow tunnel to the coffin, and withdrew the body from the end of the casket, pulling it through the tunnel. The disturbed earth was several yards from the violated coffin and, being of relatively small size, was difficult to spot.
Ed Gein, the Plainfield, Wisconsin serial killer upon whom such fictional killers as Norman Bates, Leatherface, and Buffalo Bill are based, collected bodies and body parts from the graves he robbed in the Plainfield Cemetery and the Spirit Land Cemetery a few miles north of Plainfield. To collect just the heads, as he sometimes did, he simply twisted the neck back and forth until it snapped. He never sawed off the head, he said, because he never took a knife, a hatchet, or a saw with him on his after-hours forays into the local cities of the dead.
According to "Stealing Lincoln's Body," by Thomas J. Craugwell, a pair of would-be grave robbers, commissioned by Jim Kennally, tried to rob the grave of Abraham Lincoln, but they made the mistake of including two police informants as assistants, and the undertaking was botched when one of the detectives who were lying in wait for the robbers accidentally discharged his firearm. Kennally's men fled, only to be arrested a short time later at their hideout.
As a result of the attempted robbery, Lincoln's body was exhumed and reburied inside "a steel cage, lowered into a vault, and covered with cement."
According to "The 1876 Attempt to Steal Lincoln's Body!", therobbers, Terrence Mullen and John Hugehs, were actually counterfeiters, but their "chief engraver," Ben Boyd, had bee arrested; the theft of the president's body was to have provided a means of liberating Boyd and of generating a recovery fee of $200,000.