let's make sure we're on the right path here. >> and there were other observations that set their timeline back. on jim tan's desk computer where he had apparently been working when he was killed, there were unopened e-mails going back before the weekend. >> jim is trading e-mails with an employee. and at some point after that, he clearly stops using his computer. he is no longer sending. he's no longer opening. >> and as detectives poked around that office monday night. >> how many days prior is the last e-mail check? >> four. four days. that was really a big thing for me. this is a guy who ran his own company with employees and activity. >> going back four days. that put the shooting back to that thursday night charlie came home from cornell. and a four-day-old crime scene would also explain what had been plainly obvious to the seasoned detectives nose. >> the odor of decomposition was very strong. >> the detective now believed that the emotional 911 call was bogus. now you're saying it's days earlier.