JOLIET, Ill. (AP) — The judge in Drew Peterson's murder trial gave the go-ahead Tuesday for prosecutors to introduce evidence that the former suburban Chicago police officer sought to hire a hit man to kill his third wife.

Prosecutors allege that Peterson, now 58, ended up killing his third wife, Kathleen Savio, himself in 2004. They want to bring up the hit-man evidence in an effort to demonstrate Peterson had planned to murder her for weeks or months.

Attorneys for the state didn't list the hit-man allegation on appropriate pre-trial documents — apparently as an oversight — and defense attorneys had argued prosecutors shouldn't be allowed to correct that mistake now.