Paul Egan / The Detroit News

MILFORD TOWNSHIP — Synthetic materials that were widely used for men’s clothing in the mid-1970s may have helped preserve the remains of former Teamsters president Jimmy Hoffa, one of the nation’s top forensic anthropologists said Thursday. Mary Manhein, the director of the Forensic Anthropology and Computer Enhancement Services laboratory at Louisiana State University in Baton Rouge, said Hoffa’s corpse is likely to be much better preserved if he was wearing nylon or polyester when he was killed, rather than a natural fiber such as cotton. “Polyester seems to last forever,” said Manhein, who is nicknamed “The Bone Lady” and has worked on more than 600 cases and appeared on television shows such as “America’s Most Wanted” and “Cold Case Files.” When he disappeared on July 30, 1975, Hoffa was reportedly wearing a blue Banlon shirt, which typically was made of nylon, and blue pants, which may have been made of polyester. Nylon, while perhaps not as resilient as polyester, would disintegrate much more slowly than a natural fiber, she said. Manhein made her comments as FBI investigators dug for Hoffa’s remains beneath the floor of a barn they demolished Wednesday on a Milford Township horse farm. The farm was once owned by former Teamsters official and Hoffa associate Rolland McMaster, who was questioned by the FBI about a week after Hoffa disappeared. McMaster, now 92, denies any role in Hoffa’s disappearance. Donovan Wells, another former Hoffa associate who was a caretaker at the farm and is now housed in a federal medical prison in Kentucky, has told the FBI he saw a hole dug on the farm the day after Hoffa disappeared and a cylindrical object that looked like a body wrapped in a carpet dropped inside the hole.If a body was wrapped in a carpet, that too would help preserve it, Manhein said.

Though they piled dirt from beneath the barn in a large pile and did not appear to pass it through a screen, FBI investigators were seen bringing large screens to the horse farm Thursday. If they begin to screen the dirt, “it sounds like they have honed in on a particular area,” Manhein said. “That’s a time-consuming task.”

The screens are widely used in such cases and would catch bullets or other foreign objects larger than about one quarter of an inch in size, she said.

FBI Special Agent Dawn Clenney would not say whether the FBI plans to screen the dirt. She also has declined to say how much the Hoffa search is costing or how the farm’s current owners will be reimbursed for the demolished barn or other damages.

Manhein said if FBI investigators are digging in the correct spot, they are almost certain to find something. “There would clearly be bones,” which could show if Hoffa was shot or received blunt trauma before he died, she said.

Even if Hoffa’s body had once been there and was later removed, proteins in the soil could show a body was once there, she said.

A trained eye can distinguish human bones from animal ones within minutes and DNA testing could prove whether the bones were from Hoffa, she said.

You can reach Paul Egan at (313) 222-2069 or pegan@detnews.com.