our curiosity was piqued to the point that we thought perhaps justin sullivan was using henry's identificationnd it could have conceivably been that justin dropped the i.d. card at the scene of the crime. >> but like his brother, justin denied any involvement in the murders. he said he had an alibi, that he was with friends at a nightclub, which they corroborated. then investigators asked their third suspect, william deparvine, for a dna sample. he said no. >> we don't have any probable cause at this point in time in the investigation to indicate that mr. deparvine is involved in the murder. therefore, we don't have enough information to draw a search warrant. >> without a warrant, police couldn't get a genetic sample directly from deparvine. but there were other ways. >> we were looking for him to either eat something, drink something and discard it, chew gum and discard it, or even spit so that we could swab that up. >> a team of detectives was assigned to follow deparvine everywhere he went, hoping to somehow get his dna sample. deparvine had earned a law degree while he was in prison, and