"No evidence or witnesses have been found corroborating any of the few facts" in Pedro Hernandez' statements about the 1979 vanishing of 6-year-old Etan Patz, defense lawyer Harvey Fishbein wrote, arguing that there's not enough proof to support the case.
While he has said before that Hernandez' startling arrest last year was the product of an untrue admission from a mentally ill suspect, Wednesday's filing fleshes out some key contentions.
The Manhattan district attorney's office, which has previously said there's sufficient evidence to sustain the charges, declined to comment. A judge isn't expected to rule until next month.
Etan vanished on May 25, 1979, on the first day his parents allowed him to walk to his school bus stop alone. He became one of the first missing children pictured on a milk carton, and the date of his disappearance became National Missing Children's Day.
Hernandez, of Maple Shade, N.J., was arrested last year after police got a tip that he'd told people years before that he had killed a child in New York City.
Hernandez then told authorities he'd seen Patz at the bus stop, lured him to a corner store where he worked with the promise of a soda and choked him in the basement. Hernandez said he tossed the boy's book bag behind a freezer in the basement, put the boy's limp body in a box and left it with some trash about a block away.
But nobody else reported seeing Etan actually at the bus stop and the book bag was never found, despite an extensive search for clues that likely would have included the shop basement, Fishbein says in court papers.
Hernandez, 52, was questioned from 8 a.m. to nearly 3 p.m. before his statements were recorded and he was read his rights, his lawyer says, arguing that the statements can't be considered voluntary and should be suppressed. Prosecutors have said Hernandez willingly talked with investigators.
The law surrounding exactly when a suspect being questioned must be notified of his or her rights is complex and often the subject of legal arguments.
Under New York law, a person can be convicted based only on a confession, so long as there's additional evidence that a crime was committed.
But Fishbein has said Hernandez is schizophrenic, bipolar and prone to hallucinations, so his admission can't be considered reliable. Prosecutors, however, have said there's no history of Hernandez being treated for a major psychiatric condition before his arrest, and they don't believe his confession was spurred by mental illness.