but to get a conviction, prosecutors needed to prove josh griffin was the killer. >> with not having ly had to build their case around that footprint. >> according to personnel records, griffin was the only officer to wear a size 8 1/2 thorogood shoe. so ricky novarro took a new pair of these shoes, made an impression and matched it to the shoeprint on the back of kim's sweatshirt. navarro believed it was the only one that could have created that impression. in february of 1998, officer josh griffin went on trial for first-degree kidnapping and first-degree murder. he pled not guilty. but the evidence was clear, and he was convicted of both charges and sentenced to life in prison. three years later, griffin asked to speak with investigators. and on tape, he finally confessed. >> i don't know what his motivation was, but i just know what he said. >> he admitted stomping on her back. he admitted choking her with a flashlight. he admitted handcuffing her. he admitted cutting her driver's license up into a million pieces and flushing it down the toilet. of course, he admitted to all of th