NEW YORK (AP) -- A suspect understood his right to stay silent before he confessed to killing a boy whose 1979 disappearance helped spur a missing-children's movement, a prosecution psychologist said Monday, contrasting a defense expert's view of a question under scrutiny as the case heads toward trial.

In this Nov. 15, 2012 file photo, Pedro Hernandez, right, appears in Manhattan criminal court with his attorney Harvey Fishbein, in New York. Hernandez is seen in hours of videotaped statements admitting that he choked 6-year-old Etan Patz in 1979, and then dumped his body. A Manhattan judge must decide whether Hernandez's confession can be used at trial, but a larger question is looming: Was it all made up? (AP Photo/Louis Lanzano, Pool, File)
In this Nov. 15, 2012 file photo, Pedro Hernandez, right, appears in Manhattan criminal court with his attorney Harvey Fishbein, in New York. Hernandez is seen in hours of videotaped statements admitting that he choked 6-year-old Etan Patz in 1979, and then dumped his body. A Manhattan judge must decide whether Hernandez's confession can be used at trial, but a larger question is looming: Was it all made up? (AP Photo/Louis Lanzano, Pool, File)
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Testimony could end as soon as Tuesday in a weeks-long hearing to determine whether the admissions from Pedro Hernandez -- the surprising suspect who emerged just two years ago in the disappearance of 6-year-old Etan Patz -- pass legal muster to be used at a trial. A judge will decide whether Pedro Hernandez was properly advised of his rights and mentally capable of waiving them, but the hearing doesn't encompass the issue at the center of his defense: whether the statements were true.

Hernandez, of Maple Shade, New Jersey, has pleaded not guilty to murdering Etan, one of the first missing children ever pictured on a milk carton. He vanished en route to from his Manhattan home to a nearby school bus stop.

Hernandez was arrested after police got a 2012 tip. His lawyers have said his confession was false and reflects mental illness. But while psychologists have testified for both sides, details of his mental health history are largely reserved for the potential trial. So far, the experts have discussed -- and disputed -- only his ability to comprehend what are known as Miranda warnings.

Both sides' experts agree Hernandez's IQ is around 70, a range the American Psychiatric Association considers bordering on intellectual disability.

But psychologist Michael Gerard Sweda said Monday that Hernandez scored not much below people of average intelligence on a specific test of how well someone understands the function of Miranda rights during police interrogation.

"His performance is largely unremarkable," Sweda said. He also noted that during Hernandez' videotaped confession to prosecutors, he refers at one point to an earlier mention of his right to an attorney but decides to go on talking without a lawyer.

"To me, it indicates he's heard his right, he's thinking about it," Sweda said, but "he wanted to get something off his chest."

Prosecutors showed a partial video of the testing, with Sweda asking Hernandez to define, piece by piece, what's meant by the familiar warnings of rights to stay silent and consult an attorney. Hernandez, sometimes haltingly, gives answers that often echo the questions but sometimes use his own words, such as "I don't have to say anything if I don't want to."

But a defense psychologist told the court last week that he believes Hernandez wouldn't have fully comprehended what he was agreeing to in saying he understood his Miranda rights.

"Ninety-eight percent of the population in Hernandez's age range are brighter verbally than he is," said psychologist Bruce Frumkin, who tested Hernandez' ability to understand complex questions and observed his behavior.

Prosecutors and Hernandez' lawyers have each suggested the other side's experts were flawed in their assessments.

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