Prosecutors in suburban Chicago are trying to prove something that most times is as obvious as a bullet hole or stab wound: That the death of Drew Peterson's ex-wife was a homicide and not an accident.

If a pretrial hearing is any indication, prosecutors may spend as much time on evidence to show there was a crime as they do on evidence to show who killed Kathleen Savio.

Peterson has pleaded not guilty.

The hearing in the former Bolingbrook police sergeant's case has been going on for weeks and is scheduled to resume Wednesday.

Prosecutors have been presenting witnesses to counter the 2004 finding that Savio drowned in her bathtub. One of the most important witnesses is a pathologist, who testified he found evidence that Savio was killed and struggled with her attacker.