The comment regarding the 1979 SoHo disappearance case came when Vance was asked at a press conference whether he was confident that Pedro Hernandez, 51, who last week confessed to strangling the boy in the basement of a bodega, was the killer.
Vance said he was not going to comment, not because he was "afraid" to answer, but because it's "premature for me to answer at this time."
Hernandez's confession and subsequent arrest in the Patz case has raised eyebrows because the boy's body has not been found and Police Commissioner Raymond Kelly admitted that investigators did not have any physical evidence to corroborate Hernandez's story, as of last week.
Hernandez's psychiatric history, including suffering delusions and bipolar disorder, may also come into play in the case.
Hernandez, who is being held in the psychiatric ward at Bellevue Hospital, was charged last week with Patz's murder after he confessed to strangling the boy in Soho on May 25, 1979.
Investigators have been trying to corroborate Hernandez's confession, which came just days before the 33rd anniversary of the disappearance.
Vance said he plans to "continue to work on this case in a measured, thoughtful, impartial manner," adding that he and his team will continue to gather the evidence they need to answer some of the questions raised about Hernandez's confession as well as his mental condition.
The DA also declined to comment on whether the charges against Hernandez will clear two other men whose names have been linked to the crime, Jose Ramos and Othniel Miller.
Ramos, a convicted pedophile, was found to be responsible for the murder by a civil court judge in 2004, but there was never enough evidence for a criminal murder charge, police said. Ramos remains in a Pennsylvania prison for molesting another child.
Miller, a retired Soho man, was recently eyed by police in the crime. In April, police dug up Miller's basement workshop at 127 Prince Street looking for Etan's remains.
According to published reports, police believed Eaton may have been in the workshop the night before he disappeared.