(CBS/AP) KANSAS CITY - Deborah Bradley, the mother of 10-month-old Lisa Irwin who went missing from their Kansas City home, says police told her she failed a lie detector test and accused her of being involved in her baby's disappearance.
Bradley said Friday that police never showed her the results of the test, and she denied knowing anything about what happened to her daughter. Bradley and the baby's father, Jeremy Irwin, said Lisa was abducted from her crib late Monday or early Tuesday.
Irwin, 28, said he also offered to take a polygraph test but that police said that was not necessary.
Kansas City police spokesman Steve Young declined to comment Thursday on whether the parents have had lie detector tests, citing the ongoing investigation.
Bradley explained that the police have treated them like suspects and that she in particular has been preparing for the possibility of charges being filed against her.
She said detectives told her: "You did it. You did it. And we have nothing."
Irwin said he came home from his overnight shift around 4 a.m. Tuesday, and noticed a window opened in the front of the house. After checking on his sons, 6 and 8, he says he went to the bedroom of his daughter and noticed she was missing.
Lisa's parents said they also discovered their front door unlocked and their three cellphones had been stolen, but the police spokesman said the missing phones had not produced any leads.
"The main problem I think that we're facing is that everybody (else) has an alibi," Irwin said. "I was at work. I've been cleared. All these other people we were worried about...the FBI said they've been cleared. The only one you can't clear is the mother that's at home when it happens 'cause there's nobody else there."
On Thursday, police told reporters that Bradley and Irwin were no longer cooperating with authorities in their investigation, but the family later released a statement insisting they had never stopped cooperating.
Lisa's parents reasserted their commitment to the investigation Friday, saying they are not angry with how things have gone and that they understand police have a difficult job to do.
Investigators focused their search Thursday on a heavily wooded area, sewers and an industrial park.
Lisa has blue eyes and blonde hair. She is 30 inches tall and weighs between 26 and 30 pounds. She was last seen wearing purple shorts and a purple shirt with white kittens on it. The baby is described as having two bottom teeth, a small bug bite under her left ear and a beauty mark on her right outer thigh.
Anyone with information is asked to call the TIPS Hotline at 816-474-8477.