After hearing divergent descriptions of a Chester County man's ties to the region and to Ireland, a federal magistrate yesterday denied him bail.

Sean Owen O'Neill Sr., 48, of Willistown Township, will remain in federal custody on charges of fraudulently obtaining a green card and illegally possessing a silencer, U.S. Magistrate Carol Sandra Moore Wells ruled.

O'Neill's attorneys, Vincent P. DiFabio and Kirk V. Wiedemer, said they would appeal. About 40 relatives and supporters reacted with tears and disbelief to the judge's order.

Among those who attended the hearing was Sean Owen O'Neill Jr., 19, who just gained his freedom last week after nine months in custody. He was ordered into a residential juvenile treatment program in September for fatally shooting his longtime friend Scott Sheridan on Sept. 1, 2006.

Assistant U.S. Attorney Faithe Moore Taylor said O'Neill Sr. posed a danger to the community as well as a flight risk. Since arriving in the United States in 1983, O'Neill failed to disclose a 1977 conviction for membership in an Irish terrorist organization, used fraudulent documentation to obtain firearms, and possessed at least one illegal silencer, with another being tested, Taylor said.

During a search on June 27, federal agents found the second silencer as well as a paperback titled How to Make Disposable Silencers, Taylor said.

DiFabio countered that O'Neill, a successful and civic-minded builder and developer, has both significant family and financial incentives to ensure his appearances in court.

Calling O'Neill "a very productive member of society," DiFabio detailed major projects under construction in Philadelphia, Media and New Jersey. Walking away from them would cost O'Neill millions, DiFabio said.

Taylor said O'Neill maintains bank accounts and property in Ireland, and has sufficient wealth to flee.

"He has the financial wherewithal to conceal his financial wherewithal," said Taylor. "Everything he has presented in this country is a lie."

DiFabio said people in Ireland are working to obtain proof that O'Neill, a native of Coalisland, County Tyrone, Northern Ireland, does not have a criminal conviction in that country. O'Neill used the "so-called" silencer to muffle the sound when he shot rabbits and squirrels on his 10-acre property, DiFabio said.