Investigators have followed thousands of leads, over the past six weeks, in their search for Lisa Irwin. However, according to a recently retired Kansas City police officer, the chances of 10-month-old Lisa Irwin surviving are slim. Dave Bernard, the officer in question, has handled several major homicide-related cases.

I know what they're going through and believe me, I feel for them, Bernard told KMBC News.

Bernard retired in September, days before Lisa Irwin disappeared from her crib. Although he doesn't have inside information, he does know, from personal experience, how authorities could be approaching the case.

You can speculate on (whether) she was taken and abducted and whatever, but you concentrate on what is probable, what most likely happened here, and see where that takes you, Bernard said.

Bernard was lead investigator in the 2001 Precious Doe murder. The case began with the body of a headless girl on April 28 and ran for four years before she was identified as Erica Green and her parents were held responsible.

In an effort to uncover the identity of Precious Doe (the name local media gave the body), a number of leads were followed up by the police. The investigations revealed that the girl had come to Kansas with her mother and her mother's former boyfriend, Harrell Johnson.

According to the prosecutor, Johnson kicked Erica in the head after which she died. Erica's mother, Michelle, and Johnson were charged with deliberately denying medical attention to the child when they knew that she would die without help. It was later discovered that Erica died several days after the initial assault. The couple then carried her body through a church parking lot into the woods at 59th & Kensington, where Johnson decapitated her in order to hide her identity.

In the case of Lisa Irwin, her mother - Deborah Bradley - and her father - Jeremy Irwin - are named as possible suspects. Vikki Ziegler, a top New York City family lawyer, believes that the parents have something to hide.