By Nate Raymond

BOSTON, May 6 (Reuters) - A U.S. judge declined on Tuesday to allow an Iranian-born engineer to be released on bail while he awaits trial on charges related to a deadly drone attack on a U.S. military base in Jordan carried out by Iran-backed militants last year.

U.S. District Judge Indira Talwani in Boston ruled that the risk that Mahdi Sadeghi might flee was too great to allow him to be released on bond while he awaited trial on charges that he engaged in a scheme to violate U.S. export control and sanctions laws.

"The seriousness of the charges and the weight of the evidence against Sadeghi give him incentive to flee if he is released, and Sadeghi's dual citizenship and connections to Iran give him the means to do so," she wrote.

The decision overturned a federal magistrate judge's determination in March that Sadeghi, a resident of Natick, Massachusetts, could be released on a $100,000 bond so long as he was subject to home incarceration with location monitoring.

Prosecutors had initially been open to a potential bail package for Sadeghi. But they shifted in mid-January to pushing for his continued detention after the Italian government released his co-defendant, Iranian businessman Mohammad Abedini, and allowed him to return to Iran.

That occurred after Iran released an Italian journalist, Cecilia Sala, who was detained in Tehran three days after the men were arrested. Prosecutors argued the events signaled Iran might take steps to help Sadeghi flee.

A lawyer for Sadeghi did not respond to a request for comment. Sadeghi had pleaded not guilty.

Prosecutors allege that Abedini headed an Iranian firm whose primary client was Iran's Islamic Revolutionary Guard Corps and that made the navigation system used in its military drone program.

That system was used in an unmanned drone that struck a U.S. outpost in Jordan called Tower 22 in January 2024, prosecutors said. The attack killed three U.S. service members and injured 47 others.

Sadeghi, while working at the semiconductor company Analog Devices ADI.O in Massachusetts, helped Abedini secure technology that was transferred to Iran, prosecutors alleged.

The technology Abedini obtained included the same type of electronic components used in the drone navigation system, prosecutors said.

Iran has denied involvement in last year's attack and had dismissed accusations that it imprisoned Sala to pressure Italy into releasing Abedini.

(Reporting by Nate Raymond in BostonEditing by Bill Berkrot)

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