that is, until they looked at mark unger's shoes and found a white smear. >> the state police crime lab a white speck of what they believed was paint. >> investigators sent mark's shoe along with six different paint samples collected from the resort to forensic scientist keith lamont. >> i received several known samples from various locations, from the vacation home and boathouse area. >> he bombarded the sample with infrared light, which identifies the chemical makeup of the samples in ways that can then be measured. >> paint's composition basically consists of a solvent, which is a liquid, a pigment, which is the color, and a binder, and the binder you can think of as glue. >> lamont found that the paint on mark unger's shoe was virtually identical to the paint on the railing and the post holding the railing. >> the question paint sample from mr. unger's shoe was consistent with the known paint sample from the rail. >> to investigators, this pointed to only one logical conclusion. >> we believe mark kicked that railing. and the paint scuff on the shoe certainly would suggest that. >>