The man charged with orchestrating a complex plot to blow up a jet fuel artery supplying John F. Kennedy International Airport cannot read and has limited analytical faculties, according to his lawyer.

Attorney Andrew L. Carter Jr. asked a federal judge Thursday to allow a psychological evaluation of accused plotter Russell Defreitas' "mental abilities and intellectual limitations."

Defreitas, 63, a U.S. citizen who is a native of Guyana, worked as a cargo handler at the airport until 1995. He is in custody in New York.

Carter told U.S. District Judge Dora L. Irizarry that Defreitas understood the charges against him despite his limitations. Irizarry gave prosecutors a week to respond to Carter's request.

Defrietas has pleaded not guilty to conspiracy. Three other suspects — Kareem Ibrahim, Abdul Kadir and Abdel Nur — are facing extradition proceedings in Trinidad. An indictment charges the four with conspiring to "cause death, serious bodily injury and extensive destruction" at the airport.

Prosecutors say Defreitas hatched the plan to blow up a jet fuel artery that runs through residential neighborhoods and feeds the airport in the New York City borough of Queens. The pipeline was designed to shut off when it detects heat, a feature that would have prevented the chain-reaction explosion that the plotters are accused of envisioning, authorities said.

Investigators had help from an informant described as so convincing that the suspects gave him unfettered access to their operation. Assistant U.S. Attorney Marshal Miller said Thursday that the government had recorded close to 300 hours of conversations between the informant and the defendants.

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