I would suggest using the case of Scott Peterson of Modesto, California convicted of the 2008 murder of his wife Laci Peterson and their unborn child. Little has been determined about the exact circumstances of the murder, however ample material is available on the investigation of the crime. The case drew national attention and is very well covered in the media. An excellent summary of the crime, investigation and trial is found in the first reference. The case involved investigation of Peterson’s alibis and activities, his fishing trip to the Bay Area (where Laci’s body was eventually found), his infidelity to Laci, phone taps of conversations between Peterson and his mistress, examinations of Peterson’s boat, and much, much more.
The second reference is a web site in support of Peterson’s appeal of his death sentence. It gives a somewhat different interpretation of circumstances of the case.
Several cases come to mind: (1) OJ Simpson; (2) Casey Anthony; (3) Bernie Madoff; (4) Watergate; (5) ABSCAM; (6) Martha Stewart. In each of these cases, there is significant pretrial discussion of the investigations.