Hernandez, who has a history of mental illness, was arrested last spring, 33 years after Patz disappeared off a New York City street.
Police said Hernandez had admitted to luring Patz into a bodega where he worked, near the boy's house, and choking him to death in the basement.
According to Hernandez's attorney, his client suffers from schizophrenia and has hallucinations. The lawyer said the entire case is based on statements made by his mentally ill client.
Police Commissioner Ray Kelly said at the time that police focused on Hernandez, who now lives in Maple Shade, N.J., after the Missing Persons Squad received a tip from someone who remembered Hernandez speaking of having killed a child.
The disappearance of Etan Patz is arguably the most famous missing child of New York City.
His disappearance helped spark the missing children's movement, including new legislation and various methods for tracking down missing children, such as the milk carton campaigns of the mid-1980s.
Patz was the first ever missing child to be pictured on the side of a milk carton.