A specially designated correction officer is posted outside the cell holding Aron, arraigned last week in the July 12 killing and dismemberment of 8-year-old Leiby Kletzky, the New York Daily News reported.
A mental evaluation of Aron at Bellevue declared him fit to stand trial but his attorney said Aron suffers from mental health problems.
"We believe him to have some psychiatric disorders and I believe the evaluators concurred with that," attorney Pierre Bazile said.
At Rikers, Aron is being housed away from other inmates, authorities said.
"He's in an area all by himself," a jail supervisor said. "They opened it up just for him."
Lawyers for Aron have said they will explore the possibility of an insanity defense.