PHILADELPHIA—The rape trial of a Roman Catholic priest and a former Catholic school teacher was postponed Tuesday after a lawyer in the case had a death in the family.

The Rev. Charles Engelhardt and Bernard Shero are due back in court Friday to get a new trial date.

Their case had been spun off from the high-profile trial this year of a church official charged with child endangerment for helping the Philadelphia archdiocese cover up abuse complaints. The Rev. William Lynn, 61, is appealing his landmark conviction in that case, while serving a three- to six-year prison term.

Engelhardt, 65, and Shero, 49, have pleaded not guilty to raping a former altar boy in the 1990s.

Their sole accuser is a troubled 24-year-old policeman's son. He has a long history of drug addiction and arrests for drugs and petty crimes, and his credibility is expected to be the key trial issue.

He told a grand jury that he was passed around by three predators, starting when he was 10, at St. Jerome's parish in northeast Philadelphia. He said now-defrocked priest Edward Avery sexually assaulted him after Mass. He said Engelhardt raped him after catching him drinking wine in the sacristy. And he said Shero, his sixth-grade teacher, attacked him after offering him a ride home.

Avery is serving 2 1/2 to five years in prison after admitting he assaulted the boy. Engelhardt and Shero face much longer terms if convicted at trial. A gag order prevents lawyers from commenting.