Family and friends of missing mom Stacy Peterson are scaling back on volunteer searches during the week, a family spokeswoman said.

Family friend Pam Bosco said the full search for the missing fourth wife of former Bolingbrook Police Sgt. Drew Peterson will resume next Saturday. Peterson is a suspect in his wife's disappearance and denies any invovlement.

While volunteers will hold off until the weekend, the Illinois State Police will continue searching for the missing 23-year-old during the week, Bosco said.

The FBI is expected to join the search for the Bolingbrook mother of two, opening the possibility of technical assistance of the U.S. Navy if needed.

Illinois State Police told FOX News on Sunday that "new information" prompted its appeal for more information about possible sightings of the cars that belong to Stacy Peterson or her husband, Drew, around the time that the woman vanished.

Investigators are asking anyone who may have seen the vehicles on Oct. 28 or 29 — the time the 23-year-old Bolingbrook mother's disappearance — to come forward.

Police have released photos of the vehicles: A dark Blue 2005 GMC Yukon Denali belonging to Drew and the second a purple 2002 Pontiac Grand Am, belonging to Stacy, and asked the public to call its tipline at 815-740-0678 or "America's Most Wanted" at 800-274-6388.

Both vehicles were impounded by police on Nov. 1., and are still in police possession because of search warrant seizures.

The Associated Press contributed to this report.