A Muslim scholar chosen to speak at U.S. president-elect Barack Obama's inaugural prayer service Wednesday is the leader of a group that federal prosecutors allege has ties to Hamas.

Ingrid Mattson, president of the Islamic Society of North America, is one of many religious leaders scheduled to speak at the prayer service at Washington's National Cathedral.

Mattson has been the guest of honour at U.S. State Department dinners and has met with senior Pentagon officials during the Bush administration. She also spoke at a prayer service at the Democratic National Convention in Denver.

Mattson, who was elected president of the society in 2006, is a professor of Islamic studies at Hartford Seminary in Hartford, Conn.

But in 2007 and as recently as last July, federal prosecutors in Dallas filed court documents linking the Plainfield, Ind.-based Islamic society to the group Hamas, which the U.S. considers a terrorist organization.

Neither Mattson nor her organization have been charged. But prosecutors wrote in July that they had "a wide array of testimonial and documentary evidence expressly linking" the group to Hamas and other radical groups.

Linda Douglass, a spokeswoman for Obama's inaugural committee, would not discuss the case or say whether the committee knew about it.

"She has a stellar reputation in the faith community," Douglass said Saturday night.

The existence of the court documents was first reported by Politico.com, a political website based in Arlington, Va.

The Islamic Society of North America, which describes itself as "the nation's largest mainstream Muslim community-based organization," is fighting its inclusion on a list of co-conspirators in the Dallas terrorism case against the Holy Land Foundation. In court documents, Mattson's group says it does not condone terrorism.

The court documents represent a complicated picture of the group.

Trained FBI agents

Law enforcement agencies have used the organization's annual convention as part of its outreach to the Muslim community. The group has provided religious training to the FBI, according to court documents.

Karen Hughes, a former confidante of President George W. Bush and under secretary of state, called Mattson "a wonderful leader and role model for many, many people."

All this was going on while officials in the law enforcement and intelligence community apparently had evidence that the Islamic Society of North America had ties to terrorists and to the Holy Land Foundation.

That foundation and five of its former leaders were convicted at a retrial in November of funneling millions of dollars to Hamas.

Mark Pelavin, director of inter-religious affairs for the Union for Reform Judaism — another organization participating in the prayer service — called Mattson "a really important voice denouncing terrorism."

"Clearly, Dr. Mattson has been welcome throughout the government," he said. "I haven't found anyone anywhere who's found anything Dr. Mattson has said that's anything other than clearly denouncing terrorism in quite explicit Islamic terms."