Nov. 19: Former Bolingbrook police officer Drew Peterson leaves his home on his motorcycle in Bolingbrook, Ill. Peterson's wife 28 year old Stacy Peterson was reported missing on Oct. 29.
Drew Peterson, with ex-wife Kathleen Savio, in an undated photo
The family of missing mother Stacy Peterson wants her husband to take a lie detector test to prove that he has nothing to hide about her disappearance.
Drew Peterson, 53 and a former police sergeant, is a suspect in his wife's disappearance. He denies any involvement and claims that she left him for another man. Stacy was reported missing Oct. 29 by her family after she failed to show up at a friend's house.
Cassandra Cales, Stacy Peterson's sister, wants Drew to take a lie detector test about his knowledge of a blue barrel or container that she said she saw in their garage two days before Stacy disappeared.
"He says there was no barrel," Cales said. "There was a barrel; I saw it with my own eyes. I'll take a lie detector test. I feel Drew should take a lie detector test also."
Joel Brodsky, Drew Peterson's attorney, denies any container is missing from the home.
"There never was a drum," said Joel Brodsky, Drew Peterson's attorney. "The whole thing seems like a never-ending rumor that started with comments that Stacy's sister made."
Earlier this week, Illinois State Police identified the person they think may have helped Peterson move a large blue container from his bedroom to his vehicle the day after Stacy disappeared.
A law enforcement source told WFLD FOX Chicago that the man who helped load a barrel into Peterson's SUV tried to commit suicide the next day.
Meanwhile, Peterson's attorney is disputing a report that Stacy Peterson told a clergyman in August that her husband confessed to her that he killed his former wife, Kathleen Savio, and made it look like an accident.
• Video: Brodsky Goes 'On the Record'
Brodsky told FOX News that Drew Peterson was "totally amazed and in disbelief" when he heard about the report.
"It's disturbing that a clergyman would violate his oath of confidentiality," Brodsky said.
Kathleen Savio was found dead in her bathtub in 2004, and at the time, her death was ruled accidental. Savio died shortly before her divorce settlement with Drew Peterson was finalized.
Stacy told her husband she was leaving him and divorcing him the day before she was reported missing by her family, telling him to be out of the house in a few days, according to the source.
Peterson, who recently resigned as an officer from the Bolingbrook police department, was scheduled to work at 5 p.m. Oct. 28 but called in to take a personal or sick day, Bolingbrook police Lt. Ken Teppel told FOX News.
Brodsky said the family member has a history of mental problems, alcoholism and suicide attempts. The family member might want attention or be living in "a fantasy world," Brodsky said.
FOX News' Greta Van Susteren contributed to this report.