SAO PAULO — Brazilian police have detained an 83-year-old priest after a congressional hearing produced allegations he molested boys as young as 12, fueling a growing scandal involving Roman Catholic clergy across Latin America. The pedophilia allegations against Msgr. Luiz Marques Barbosa are the most lurid of sexual scandals to hit the church in one of its most powerful centers recently, driven home by a TV station broadcast of a sex tape of him in bed with a 19-year-old widely distributed on the Internet. Sen.