The Beacon School’s field trips to Cuba have generated the interest of the Treasury Department, which is investigating a community group that may have organized the trips.

An official at the Treasury Department’s Office of Foreign Assets Control, Dale Thompson, wrote to Pastors for Peace/Interreligious Foundation for Community Organization last year to request records and notify it that his office was “currently conducting a civil investigation of this matter.”

The group supports travel to Cuba, and participants in the Beacon School field trips say the group organized their travel to the communist country. The trips, at least some of which violated federal law, do not appear to have received authorization from top officials at the city’s Department of Education. They did, however, receive the written endorsement of at least two politicians, Lieutenant Governor David Patterson and Rep. Jerrold Nadler. Both later said they were unaware the trip was being undertaken in violation of the federal travel ban.

The city’s Department of Investigation is also looking into the field trips.

In all, Beacon School educators chaperoned at least six trips to Cuba. The last trip drew attention after the group was stopped by customs agents in the Bahamas. The Treasury Department letter, which is not dated but is from last year, instructed the group to compile a report describing its role in all the Beacon School trips. The letter also requests details on any money the groups received from student participants or outside contributors. The federal investigation was first reported in the New York Law Journal.

It is not known whether the Treasury Department has made demands to the city’s Department of Education.

A lawyer for the New York Civil Liberties Union, Palyn Hung, who represented the Interreligious Foundation in recent litigation relating to the investigation, referred a call for comment to the group. A spokesman there did not return a call for comment.

The Interreligious Foundation is headquartered on West 145th Street. The group’s Web site says the American government “says you can’t go to Cuba and see things for yourself. We say you should!”

As part of a court settlement in 2000 with the Treasury Department, the Interreligious Foundation agreed it would not be eligible to receive authorization to provide services in connection with travel to Cuba.

The city’s investigation into the trips was stalled when the Interreligious Foundation went to court to oppose subpoenas it had received from the city’s special commissioner of investigation for New York City public schools, Richard Condon.

Last week, a judge, Judith Gische of state Supreme Court in Manhattan, upheld the city’s subpoenas.

Those subpoenas request information including permissions slips, itineraries, and payments or contributions received from students and educators, the decision said.

In court papers, the foundation has not confirmed that it was involved in arranging the school trips.

A spokesman for the Treasury Department declined to comment.