but detective peglow was no rookie.nvestigation into charlie tan and what happened inside that home was just getting started. >> one of the investigators found what appeared to be newly taken passport photos, along with a list of prominent local defense attorneys. >> that's interesting. >> yes, sir. >> his story is, "i had to do it." but you're not takin' that at face value, huh? >> correct. >> reporter: coming up -- a discovery on jim tan's computer triggers suspicions about his time of death. >> so how many days prior is the last email checked? >> four. that was really a big thing for me. >> reporter: when dateline continues. ♪ i thought i was managing my moderate to severe ulcerative colitis. but i realized something was missing... me. the thought of my symptoms returning was keeping me from being there for the people and things i love most. so, i talked to my doctor and learned humira can help get, and keep,uc under control when other medications haven't worked well enough. and it helps people achieve control that l