Police say school volunteer Deonte Carraway, 22, made pornographic videos with children during school hours and on the grounds of Judge Sylvania W. Woods Elementary School (Mark Gail/For The Washington Post)

The confession of a former Prince George’s County elementary school teaching assistant arrested on child pornography charges should be tossed because it was not given voluntarily, according to a legal argument filed by his lawyers.

The attorneys representing Deonte Carraway argued in legal filings that the 22-year-old — who was in special-education classes for all of his schooling and has an IQ of 63 — did not fully understand his rights when he spoke to law enforcement investigating the case in February.

“In a psychological evaluation, it is noted that, he exhibited significant cognitive deficits . . . which placed his overall intellectual functioning in the deficient range,” Carraway’s attorney’s wrote in documents filed Friday in federal court. “Numerous cases hold that limited intelligence and mental disability weigh heavily against a finding of voluntariness.”

Carraway has been charged federally with 13 counts of sexual exploitation of a minor and production of child pornography after police allege he abused and filmed inappropriate behavior with children who were as young as 9. Carraway also faces related local charges connected to the case and is being held at the county detention center.

Deonte Carraway (Prince George's County Police Department)

Carraway abused and filmed students during the school day and on the grounds of Judge Sylvania W. Woods Elementary School since at least January 2015, police have said. Carraway also abused children at a community center, church and in private homes, claiming at least 17 victims, according to police.

The case has prompted the county school system to conduct a review of its policies and procedures to determine how Carraway was permitted enough time alone to allegedly perpetrate such acts and why other adults in the school did not notice or did not report problems.

The Carraway case has also prompted at least five civil suits against the school system, including a class-action lawsuit.

Carraway distributed phones to some of his victims and communicated with them on the devices through social media, police and prosecutors allege.

Carraway’s attorneys have also requested that the judge block evidence collected from at least two cellphones connected with the case, saying the information was obtained with “a tainted search warrant.”

“The affidavit underlying the warrant did not establish probable cause to believe evidence of a crime would be found at the location,” according to a legal motion tied to one phone.

On another phone, Carraway’s attorneys argued that police searched it without a warrant.