A friend of former Illinois police officer Drew Peterson's ex-wife says her friend was so afraid of Peterson that she installed a deadbolt lock on her bedroom door and slept with a kitchen knife under her mattress.

Kristin Anderson testified Wednesday that Kathleen Savio told her Peterson once put a knife to her throat and threatened to kill her. Anderson lived at Savio's home for two months in late 2003.

The testimony came during a hearing to determine what hearsay evidence will be allowed at Peterson's upcoming murder trial.

The former Bolingbrook police officer has pleaded not guilty to first-degree murder in Savio's 2004 death. The death was initially ruled accidental but reclassified a homicide after the 2007 disappearance of Peterson's fourth wife, Stacy Peterson.

He has denied any wrongdoing.