Pedro Hernandez, a former store clerk in Manhattan, was arraigned by video feed from Bellevue Hospital Center, where he was taken following his arrest Thursday. Police said Hernandez confessed to luring Etan with a soft drink and then strangled him. He allegedly put the boy's body in nearby trash.
Hernandez is being held at Bellevue on suicide watch, CNN reported, citing law enforcement sources.
Judge Matthew Sciarrino denied bail after Harvey Fishbein, an attorney for Hernandez, said his client has a "long psychiatric history" of schizophrenia, bipolar disorder and hallucinations, CNN reported. Sciarrino granted Fishbein's request for a full psychiatric evaluation for Hernandez.
Etan's disappearance on May 25, 1979, focused national attention on the issue of missing children. He was the first missing child whose face appeared on milk cartons.
New York Police Commissioner Ray Kelly said investigators found Hernandez due to a tip prompted by recent media coverage of the case. He had allegedly confessed to family members over the years, police said.
Hernandez, who was 19 at the time of Etan's disappearance, has no prior criminal record, CNN reported.
Kelly said Hernandez appears remorseful.
A law enforcement CNN did not identify said Hernandez "began making statements that he wanted to die, and a psychiatric evaluation was ordered," after Hernandez arrived at the hospital.