The Illinois Senate voted Wednesday to allow as evidence hearsay statements from dead witnesses, the Chicago Sun-Times reported Thursday.
The legislation would take effect immediately if approved next week by the Illinois House.
The proposed law could be used in the case of Peterson, who vanished at 23 years old last year from her Bolingbrook home, and in the unsolved homicide case of Kathleen Savio, the Sun-Times said.
Both women had been married to retired Bolingbrook Police Sgt. Drew Peterson, who state police say is a suspect in Peterson's "potential homicide," the Sun-Times reported.
A clergyman allegedly has said Stacy Peterson told him Drew Peterson killed Savio, the Sun-Times said, noting Savio once sent a letter to a prosecutor that said, Peterson "knows how to manipulate the system, and his next step is to take my children away. Or kill me instead," the Sun-Times reported.