Crime scene investigators went back on Friday to the home of a 35-year-old hardware store clerk accused of abducting an 8-year-old Brooklyn boy off the street and killing him.
Officials say they recovered the towel allegedly used to suffocate the boy, as well as the knives used to dismember his body.
The devastated family of the child posted a note outside their home on Friday, thanking the community "from the depths of our mourning hearts" and asking for privacy.
Levi Aron pleaded not guilty to charges of first-degree murder and kidnapping on Thursday and was ordered held without bail. He is accused of snatching Leiby Kletzky on Monday and taking him to his apartment, where police say he suffocated and dismembered him.
The city medical examiner is still working to determine the exact time of death.
Aron was taken to Bellevue Hospital for a psychiatric evaluation, sources said, as investigators returned to his house to comb for more evidence.
His attorney, Pierre Bazile, said Aron hears voices and has hallucinations. He said Friday that he and his client await the results of the psych exam and have no further comment.
As Aron was led into and out of the courtroom for Thursday's arraignment, other prisoners awaiting arraignment at the courthouse could be heard jeering and yelling at him.
Aron wrote in a confession exclusively obtained by NBC New York that: "I understand this may be wrong and I'm sorry for the hurt that I have caused."
Read a redacted transcript of Aron's alleged confession here.
Brooklyn District Attorney Charles Hynes says investigators are looking into whether Aron had any improper contact with children in the past. Detectives also have been examining three computers seized from his home.
Police Commissioner Ray Kelly said Aron has shown "no remorse," at times giggling when speaking with investigators.
Kelly said the boy appeared to have defensive wounds, which leads investigators to believe he fought back when he was being smothered to death.
Aron had told police in his confession that he let the boy sleep while he went to work on Tuesday, but Kelly said the child appeared to have been restrained. Officials think he might have been tied up in the apartment while Aron went to work.
In his confession, Aron told police that he took the boy to a wedding upstate on Monday, the night he is accused of abducting him. Kelly said witnesses saw Aron there, but so far have no information that the boy was there.