investigators wanted to see if they could link o'quinn to the two bottles of propofol. the vials of propofol have a national drug control number and a lot number. >> those specific bottles of propofol were shipped by mckesson distributors out of lakeland, florida. >> from there, they were shipped to the shands hospital at the university of florida. >> they were shipped during the time period of when oliver o'quinn was employed there. >> specifically, they were placed in an automated dispensing machine in the hospital icu. >> i traced it to a machine that operates kind of look a soda machine. you punch in the patient number, and it drops a bottle of a pharmaceutical in your hand. >> to get the propofol from the dispensing machine, a hospital employee had to enter his employee number. and whose code was entered to get these two vials? registered nurse oliver o'quinn. >> so i actually had that propofol all the way from the manufacturer in massachusetts to oliver o'quinn's hand in the surgical intensive care unit at the hospital. >> all investigators needed now was a sample

. >> facing increasing pressure, o'quinn left ireland and flew to the west african country of senegal, where he was immediately turned over to u.s. authorities. once in custody, investigators got a court order to obtain o'quinn's dna sample, which was then compared to the dna found on the syringe cap. it matched. >> to me, i would equate that with getting the suspect's fingerprint off the trigger of the murder weapon. >> oliver made a great many mistakes, thank goodness.