While she was working inside, a fellow worker rolled the stone closed, encasing her in stony darkness and silence, she said. She found a bench that lined the walls of the tomb's central chamber and lay down on it, enjoying the cool stone wall's feel against her face. As she did so, she thought about the temperature inside and later began digging into literature on the Shroud of Turin and whether anyone had tried to determine the temperature inside Christ's tomb.

A resulting article, "New Evidence May Explain Image on Shroud of Turin," published in Biblical Archaeology Review, July/August 1986, was co-written with a researcher named Joseph Kohlbeck.

Kohlbeck was listed as a resident scientist at Utah's Hercules Aerospace Center. It was reported that Kohlbeck, with assistance from Richard Levi-Setti of the Enrico Fermi Institute at the University of Chicago, compared dirt from the shroud to travertine aragonite limestone found in ancient Jewish tombs in Israel.

Kohlbeck's dust particles were taken from sticky tape samples that researcher Ray Rogers, from the 1978 shroud investigation team, had taken from the Shroud of Turin and compared with Nitowski's samples.

According to several scholarly papers and a book by author Ian Wilson called "The Blood and the Shroud," the particles of dirt on the Shroud of Turin provided a close chemical match to the samples Nitowski took from the tombs. At the time, Kohlbeck acknowledged that his work was not proof that the shroud was in Jerusalem and that there might be other places in the world where aragonite has the identical chemical composition.

Barrie Schwortz, a Jewish researcher and member of the original 1978 Shroud of Turin Research Project (STURP) team, said his knowledge of research on the shroud leads him to believe the image on the cloth "is not the product of a scorch," even a very mild one like Nitowski described.

"There are many known scorches on the Shroud from the fire in 1532. Scorched linen will fluoresce, and as expected, the scorched images (on the shroud) do show fluorescence, but it's not a product of heated linen in the image the way a scorch would be. I believe there is ample scientific evidence to support that."

Schwortz now owns and operates an active Web site on the shroud, www.shroud.com. He said he believes the shroud is most likely authentic, but moving from skeptical science to active advocacy of that position took him about 18 years of study.

"I became an advocate based on direct involvement and personal examination of the cloth. I expected to see the brush strokes (that many have speculated were used to paint the image) and come home. But there is no paint. This is not a painting. Then it became a question of what is it."