In a letter to U.S. Customs and Border Protection, Rep. Ayanna Pressley, Sen. Ed Markey, and Sen. Elizabeth Warren called for information about why a Northeastern University student from Iran was removed from the country despite a judge’s stay of deportation order.

Mohammed Shahab Dehghani Hossein Abadi, 24, was detained by CBP and deported shortly after landing at Logan Airport Monday night.

It is not yet clear why Northeastern University student Mohammed Shabab Dehghani Hossein Abadi, who his lawyer claims had a legal student visa, was detained and deported.

The Massachusetts lawmakers’ letter was addressed to Customs and Border Protection Acting Commissioner Mark A. Moran.

“We write to express our serious concern regarding the pattern of U.S. Customs and Border Protection (CBP) targeting Iranian students for secondary inspection and, in many cases, its subsequent issuance of expedited removal orders, as the recent case of Mohammad Shahab Dehghani Hossein Abadi exemplifies,” the letter reads. “We are also deeply troubled by the manner in which CBP handled the detention and removal of Mr. Dehghani, especially its apparent refusal to comply with an emergency federal court order to stay his deportation.”

The full text of the letter can be read here.

Pressley, Markey, and Warren also note “at least seven other cases” of Iranian students being deported despite having passed security checks, as Shahab had. Lawyers say at least ten Iranian students have been deported in the past year.

The lawmakers admonished CBP for defying the federal judge’s stay order.

“At a minimum, we would expect CBP to have since recognized that it is not above the law and cannot defy a federal court order,” they wrote. “It is highly concerning to us that CBP has instead decided to repeat this unlawful behavior.”

On Twitter, the ACLU applauded the lawmakers’ letter.

NBC News quoted a federal law enforcement official familiar with the case saying Shahab was deported because “he allegedly has familial connections to individuals ‘intricately involved’ in a U.S. designated terrorist organization.”

Lawyers pointed out that Shahab had a legal student visa, which would have required that he pass extensive vetting.