discovered that the sweatshirt was made up entirely of acrylic fibers. palenik could find no acrylic fibers on vincent holmes' shirt, but he did find some on william buck's shirt. but were these fibers from the sweatshirt? most clothing isn't dyed with just one color. usually it takes a combination of colored dyes to get just the right shade. to identify the chemical makeup of the blue fibers, palenik placed them on a plate of silica gel and dipped them into a solvent. >> the solvent mixture travels its way up the plate. it starts to separate the dyes into individual components. sort of a gratifying moment as a scientist to see each dye separating out. >> the fibers were unusual. most contain three or four color mixtures.