More than a year after confessing to police, the mentally challenged ex-bodega worker accused of the 1979 killing of Etan Patz was confused about whether he had committed the crime, a defense psychologist testified Tuesday at a hearing on the confession.

"He said a lot of things," said Bruce Frumkin, who interviewed Pedro Hernandez 13 months after his 2012 confession. "He would give me different versions of what transpired, some of which didn't make any sense. . . . At some points he was indicating confusion, he didn't know if it happened."

Frumkin, at a state Supreme Court hearing in Manhattan on whether to admit the confession at trial, said Hernandez's IQ was in the lowest 2 percent in tests dating back to 1992. Hernandez didn't intelligently waive his right to remain silent when he talked to detectives, Frumkin said.

While Hernandez knew about Miranda warnings from watching "Law and Order," Frumkin said, he believed once he talked to police before he got his warnings, he couldn't stop, and if he didn't talk, "the judge is going to think he is guilty."

Hernandez, 53, confessed in May 2012 to the abduction of 6-year-old Etan after he saw the boy waiting for a bus near the SoHo bodega where he worked. A relative told police Hernandez might be involved.

His lawyers say besides having a low IQ, Hernandez is bipolar and schizophrenic, fantasized his role in the crime, and was manipulated by NYPD detectives during 7 1/2 hours of unrecorded questioning before he was advised of his rights.

Hernandez's trial on murder and kidnapping charges is set for January. Prosecutors have no known evidence other than his confession. Etan's body was never found.

Frumkin, an expert on false confessions and Miranda waivers, could be a trial witness. On cross-examination, prosecutor Joan Illuzzi-Orbon peppered him with questions. After he testified that Hernandez went back and forth on whether he actually killed Etan, she noted that he had also told the psychologist he tried to "block out" what happened since 1979.

"Did he tell you," she asked loudly, "why he would have to block out something for 32 years that didn't happen?"

Illuzzi-Orbon asked Frumkin how he knew Hernandez wasn't just a manipulative liar pretending to be unintelligent and unable to understand Miranda warnings. She said he had functioned effectively in other settings -- completing 11th grade, holding jobs and learning car-mechanic and accordion skills.

"Would it surprise you to know," she added, "he did his own pro se divorce?"

During follow-up questioning, defense lawyer Harvey Fishbein showed Frumkin a copy of the divorce papers -- a preprinted, fill-in-the-blanks form from "The Divorce Center" -- and a high-school transcript with Cs, Ds and Fs.

He asked whether Hernandez was a successful student. "No," Frumkin answered.

The hearings resume Monday.