A warden's decision to ban a convicted killer from preaching to fellow inmates violates the prisoner's right to practice religion, his attorney told a federal appeals court Wednesday.

Wesley Spratt is serving a life sentence in a maximum-security prison in Rhode Island for the 1995 murder of a parking lot attendant in Providence. He said he preached in prison for about seven years, under the supervision of a minister, after what he describes as a calling from God.

But when a new warden took over in 2003, he barred Spratt from preaching, saying it was dangerous to give a prisoner such a position of authority.

Spratt's attorney, Lynette Labinger, said her client's Christian preaching was done under supervision and never incited other inmates or posed a security problem.

"He did it weekly, he did it openly, he did it incident-free," Labinger told a three-judge panel of the 1st U.S. Circuit Court of Appeals in Boston.

Labinger said other inmates at the state prison in Cranston are given positions of authority, such as acting as a librarian or serving on the food line.

Patricia Coyne-Fague, an attorney for the state Department of Corrections, countered that those positions "don't involve an inmate standing before a group of inmates and expounding upon Scripture or any other work."

A federal judge last June upheld the preaching ban, saying the state had an interest in maintaining a safe prison. The circuit court panel did not indicate when it will rule.