A Catholic priest who sexually assaulted an altar boy in Louisiana is in prison, and a diocese has paid a settlement to the victim’s family. Now the diocese’s bishop has punished the victim’s father, a former deacon, with the Church’s highest censure: excommunication.

It was the latest turn in a yearslong battle pitting the former deacon, Scott Peyton, and his family against the Diocese of Lafayette.

The Peytons and the diocese have found themselves on opposing sides of a state law that gave childhood sexual abuse victims more time to file lawsuits.

The law, which was passed in the State Legislature in 2021 but struck down on Friday by the state’s highest court, did not apply exclusively to victims of clergy abuse. However, the law prompted new civil suits against Louisiana churches and clergy members who worked for them.

The battle has its roots in 2018, when Mr. Peyton’s son Oliver accused the parish priest at St. Peter Catholic Church in Morrow of sexually assaulting him three years earlier, when he was 16. Scott Peyton served the same priest, Father Michael Guidry, as a deacon.

While the St. Landry Parish Sheriff’s Office investigated the allegations, Father Guidry was suspended from his church duties and later confessed to the assault, according to court records.