One neighbor says he helped Peterson haul a large barrel that was warm to the touch in the Petersons' SUV, reports CBS' The Early Show.
Police also told members of Texas EquuSearch, which assisted law enforcement, family and friends in the search for Stacy Peterson, to focus on areas of water in their search for the barrel, Tim Miller, founder and director of the private group, said Tuesday.
"They actually even gave me a picture of what we might be looking for," Miller told The Associated Press. "It was certainly large enough to put her body in, she only weighed about a hundred pounds."
Illinois State Police did not immediately return repeated messages from The Associated Press Tuesday evening.
Peterson, 23, was last seen on Oct. 28. Authorities have said her husband, Drew Peterson, is a suspect in her disappearance and have called her case a possible homicide.
Peterson's disappearance led authorities to re-examine the circumstances of the 2004 death of Drew Peterson's third wife, Kathleen Savio. Authorities have said her death may have been a homicide staged to look like an accidental bathtub drowning.
A coroner's jury initially ruled that Savio's death was accidental, but nationally known pathologist Dr. Michael Baden examined her exhumed remains at her family's request and determined her death was a homicide. The state's attorney's office has said it could be weeks before investigators have official results from an autopsy.
Drew Peterson, 53, has denied any involvement in either case and said he believes his 23-year-old wife left him for another man and is alive. His attorney did not return calls.
On Tuesday, Peterson emerged from his suburban Chicago home with a hand-held video camera and told the horde of reporters surrounding his house that they made him feel like a prisoner.
"Showing what it's like to be Drew Peterson," he said.