cross arms. in fact, you can even see elongated fingers. >> leading a team of 40 scientists, jackson set out to investigate the shroud using tools at the forefront of science. >> we really didn't know what we were going to find. was this going to be a painting? was it going to be something else? >> working around-the-clock for 5 days, the scientists reached conclusions that seemed to advance the authenticity of the shroud and deepen its mystery. >> the fibers themselves are all individually colored, so there's no evidence of something that you would expect, say, from a paint medium. we don't see that. it doesn't penetrate through the thickness of the cloth. it lies just on the very surface. the question is why -- why is that? >> jackson and his team also wanted to investigate the dark marks that appeared to be bloodstains.