FREDERICK, Md. (AP) -- A well-preserved human forearm that was once displayed near the Antietam National Battlefield as "The Arm of the Unknown Soldier" is now grabbing the Halloween spotlight at the National Museum of Civil War Medicine.
Officials at the Frederick, Maryland, museum call the naturally mummified relic the highlight of their first "Behind the Screams" Halloween tour of the facility - a 19th century embalming parlor that they dub "the most haunted building in Frederick."
But they also insist it's not just a marketing gimmick.
"We don't want it to be a scary Halloween prop," said curator Lori Eggleston. "This is the arm of a 16-year-old boy who probably died on the battlefield."
The Civil War museum is exhibiting the limb as an example of a typical wound from the clash near Sharpsburg on Sept., 1862, that left about 23,000 soldiers dead, wounded or missing on the bloodiest day of the Civil War. The forearm's skin and tendons appear to have been violently twisted, making it unlikely that the arm was surgically amputated.
"Medical specimens aren't torn off of bodies," said Eggleston said.
However, it's far from certain the arm was torn off in battle.
Smithsonian Institution anthropologists who examined the limb for the Frederick museum were unable to authenticate it as a battlefield relic. They say it belonged to an unidentified white male of about 16 - five or six years younger than the average soldier - who probably hailed from New York, Pennsylvania or Ohio, based on forensic evidence of his diet. There is a smaller possibility he was from the local area, the researchers found.
"The authenticity of the arm as a Civil War relic is highly questionable due to inconsistencies in its collection record with evidence from the analysis, historic documentation, and interviews with local residents," Karin S. Bruwelheide and Douglas W. Owsley of the Smithsonian's National Museum of Natural History wrote in their report.
The muddy-looking arm was donated anonymously to the museum in 2012 after decades on display at a roadside museum in Sharpsburg.
The limb purportedly was found two weeks after the battle by a farmer who was said to have pickled it in brine before giving it to a local physician, who supposedly preserved it with embalming fluid.
But researchers found no evidence of chemical preservation. Rather, the arm appears to have dried out naturally, either in the open air or under a light soil cover - like the shallow graves in which those slain in battle were hurriedly buried before their remains were moved to the Antietam National Cemetery.
"It is possible that the arm was uncovered during this process. It seems unlikely however, that it would have remained unplaced in a grave," the Smithsonian anthropologists wrote.
Researchers also couldn't verify that the limb was ever in the possession of a local doctor. They cited another account that it was found on the battlefield around 1900 by a local patent medicine dealer named Daniel or Peter Fahrney. Human remains have been found at Antietam as recently as 2009.
Whatever its origin, the limb deserves respectful treatment, Eggleston said.
"I think as long as we are respectfully telling the story and using it as an opportunity for people to learn about it, I think we're doing OK," she said.