NEW YORK -- Expressing concern about a possible cover-up by Long Island's Roman Catholic diocese, a district attorney Thursday announced he was convening a special grand jury to investigate allegations of sexual abuse by priests and how the allegations were handled by the church.

"From what we have received by way of information so far, it does appear that there has been a cover-up," Suffolk County District Attorney Thomas Spota said.

"The grand jury is being formed because of the serious allegations of sexual misconduct by accused priests," Spota said. "The time has come to investigate not only that matter, but what the Diocese of Rockville Centre has done."

Under New York law, grand juries can subpoena evidence and witnesses, issue indictments or find that subjects did not break the law.

The grand jury, to be convened within weeks, is considered a bold step in the growing examination of the church's handling of allegations of sexual abuse of minors at the hands of priests. Legal experts say it would be the first special grand jury convened solely for the purpose of conducting a broad examination of sexual abuse allegations against clergy.

First time

"This is the first time I'm aware of in the country that a prosecutor has had the moral courage to investigate," said Michael Dowd, a New York attorney who has represented several sexual abuse victims. "This is a grand jury that is hopefully looking, if it's justified, to indicting higher-ups or the diocese itself as an institution."

The Diocese of Rockville Centre serves 1.5 million Catholics in Nassau and Suffolk counties. Bishop William Murphy turned over information on abuse cases to the counties' district attorneys last month.

Diocese spokeswoman Joanne Novarro said Thursday that she was "puzzled" by Spota's comments. "We've been cooperating all along and we've said we're going to cooperate with the grand jury," she said.

Patrick Scully, a spokesman for the Catholic League, said that as long as the grand jury follows "normal legal means," he does not anticipate any problems. "The problem comes when something becomes an extraordinary means to go after priests," he said.