A federal judge on Wednesday night expressed skepticism about the Trump administration’s reasons to avoid seeking the return of scores of Venezuelan immigrants who had been expelled to El Salvador in March, saying he was inclined to order officials to provide more information on the arrangement between the American and Salvadoran governments.

The questions raised by the judge, James E. Boasberg, came at a hearing in Federal District Court in Washington, where lawyers for the deported men claimed that because the administration had sent them to a prison in El Salvador under an apparent agreement with the Salvadoran government, it should be responsible for facilitating their return to U.S. soil.

Over the past several weeks, lawyers for the American Civil Liberties Union have secured orders from judges in several courts across the country stopping the Trump administration from using the Alien Enemies Act, an 18th-century wartime law, to summarily deport Venezuelans accused of being gang members to a terrorism prison in El Salvador.

But at least so far, the lawyers have not been able to protect about 140 Venezuelan migrants who are already in Salvadoran custody after the United States sent them on charter flights under the act on March 15.

The hearing in Washington on Wednesday night was held in part to debate two crucial issues: what role the Trump administration played in having the men detained in the Salvadoran prison in the first place, and whether officials could be held accountable for bringing them back to the United States.

In seeking to answer the first of those questions, Judge Boasberg pressed a Justice Department lawyer about a recent statement by President Trump concerning Kilmar Armando Abrego Garcia, a Salvadoran man who was wrongfully expelled to El Salvador in the same set of flights as the Venezuelan migrants.