Updated

A man accused of kidnapping and killing an 8-year-old boy who asked him for directions was ordered Thursday to undergo a psychological evaluation after his lawyer told a judge that his client might be mentally ill.

"He has indicated to me that he hears voices and has had some hallucinations," attorney Pierre Bazile said.

Levi Aron is charged with luring Leiby Kletzky to his home on Monday, and then smothering him and chopping him up when he learned that a search was under way for the missing Brooklyn boy. Detectives found the child's feet in Aron's freezer.

The 35-year-old Aron pleaded not guilty Thursday afternoon at his arraignment at a Brooklyn courthouse. He entered the courtroom looking disheveled and pale.

As he was led out from the courthouse holding pens, other inmates screamed obscenities at him.

Police and prosecutors have said he has confessed to the crime.

Investigators have said that Leiby may have been tied up and tried to fight off his captor before he was killed.

At a news conference, Police Commissioner Raymond Kelly said Aron had scratches on his arms, wrists and elsewhere -- a sign "there was some kind of struggle." There also were marks on the boy's remains that could have been caused by restraints, the commissioner added.

A preliminary medical examination indicates Leiby was "smothered or suffocated," but it remained unclear when that happened, Kelly said.

Kelly also confirmed reports that Aron had given a written confession in Leiby's gruesome slaying that ended with, "I'm sorry for the hurt that I caused."

Beyond that, "he hasn't expressed any remorse," Kelly said.

Leiby vanished late Monday afternoon after getting lost during what was supposed to have been a seven-block walk from his day camp to where his mother was waiting for him.

New York Police Department investigators later used a surveillance video to trace the missing boy to Aron, a hardware supply store clerk whom the boy had apparently asked for directions.

Detectives found the boy's severed feet, wrapped in plastic, in the man's freezer, as well as a cutting board and three bloody carving knives. A plastic garbage bag with bloody towels was nearby.

Aron, 35, told investigators that after taking Leiby off the street Monday, he brought the boy to a wedding in the suburb of Monsey and spent several hours there, Kelly said. Other guests at the wedding confirmed Aron was there but didn't see the boy, the commissioner added.

By the time the pair returned to the city, it was so late that Aron decided to take Leiby to his home to sleep and left him there Tuesday when he went to work, according to the police version of the confession. Kelly said the hardware supply store confirmed that he showed up as usual that day.

The suspect told police he killed Leiby when he got home after being spooked by a massive search for the boy in his tight-knit Hasidic community in Borough Park.

"When I saw the fliers, I panicked and was afraid," he said, according to police.

Aron also recounted how he dismembered Leiby in details Kelly said were too "grotesque" to make public.

In his confession, Aron described how he put some of the body parts in a freezer and took a shower, police said. He then put some remains in a suitcase and drove around with it for 20 minutes before putting the suitcase in a trash bin.

Aron has denied he molested the boy, but Kelly said police still consider that a possibility.

Brooklyn District Attorney Charles Hynes said he plans to charge Aron with felony murder and was also investigating whether he might have had any improper contact with children in the past.

Bazile said he expected his client to be arraigned Thursday.

"From the Aron family, they'd like to extend their condolences to the family of the boy," he said, adding they would let the justice system work and wouldn't make any further statements.