>> reporter: one a.m. in a little room downtown. already a long day for mankin, whose back is to the camera, and tschudy, at the table, facing bob. >> we're tryin' to figure out what happened. and, uh, maybe -- when's the last time -- you saw her, spoke with her? >> what do you mean, what happened? i mean, i don't -- >> we have -- we have good reason to believe that anna was murdered. >> oh, my god. >> yeah. >> no. god. how -- how would something like that happen? how would that happen? >> do you know of anybody who would want to harm anna? >> no. i mean, why would somebody want to harm anna? >> reporter: the detectives needed to nail down bob's timeline for the evening anna was murdered: tuesday, january 13th. >> i wasn't really doing anything yesterday. you know, watching tv more than anything else. >> reporter: bob's alma mater, ohio state, had won the national championship monday night, and