one, a warehouse worker named joe siegert, had seemed unusually unemotional about michelle's death whenfirst questioned. >> he was one of the ones that made it to the top of the list. >> joe presents himself as a loner. kind of a dry, dark sense of humor, and personality. >> reporter: the other guy at the time clock that morning was doug tungate. doug was a temporary employee. a newcomer to thermo fisher -- and an outsider. >> we started looking into his past. saw that he had a couple felonies, and some alcohol issues. so, we thought, "hmm, this might be a good guy to look at." >> reporter: then there was david dooley, the janitor. he and his wife janet had cleaned at thermo fisher for years. david was one of the two to find michelle's body. >> detective mcvay interviewed him the day of the homicide, and really nothing that put him to the forefront of anyone's mind. >> reporter: and last, there was ed yuska. he was the supervisor who called 911 after finding michelle. >> the blood is right by her office door. it looks like she never got in her office. >> reporter: detective stahl found