Idaho Supreme Court dismisses abuse lawsuit against Boise diocese

The Idaho Supreme Court has dismissed a lawsuit accusing the Roman Catholic Diocese of Boise and St. Mary's Catholic Church in Moscow, Idaho, of covering up the danger posed by an allegedly abusive priest, ending a yearslong legal fight over the case.

The court ruled Aug. 11 that plaintiff Peter Steven Leriget failed to show the diocese and parish committed "constructive fraud," a legal theory requiring proof of a relationship of trust distinct from that of an ordinary parishioner. The ruling upholds a district court's earlier decision granting summary judgment to the Church.

Leriget alleged he was sexually assaulted by Father Patrick O'Sullivan in his family's Moscow home in 1968, when he was 9 years old and attending St. Mary's Catholic School. Father O'Sullivan, who died in 1993, allegedly abused Leriget when the priest was babysitting him, according to the suit. Leriget said he did not disclose the abuse until 2019, when he told a therapist. He informed his wife, mother, and attorneys the following year and sued the diocese and parish in 2021.

Leriget argued the diocese committed fraud by holding out Father O'Sullivan and other priests as universally trustworthy while concealing the danger he could pose, creating a relationship of trust that Father O'Sullivan then exploited. His attorney, Melanie Baillie, argued before the court in April that the priest, who wore his collar during frequent visits to the family's home, "was never off-duty." 

Leriget’s legal team further argued that references in the priest’s personnel file to his problems with alcoholism were code for pedophilia. The state supreme court found that Leriget’s own testimony that Father O’Sullivan would come over to his family’s house for dinner and drank “a lot of alcohol” pointed to the priest’s legitimate problem with alcohol abuse, not pedophilia.   

In response to arguments that the Diocese of Boise and St. Mary’s Parish knew about abusive priests and failed to inform the public, the diocese’s attorney Stanley Welsh stated at an April 2026 hearing that the diocese received its first report of abuse by any clergy member in 1985 and besides Leriget no one else has come forward with a complaint against Father O'Sullivan. 

The Supreme Court sided this month with the diocese, ruling that Leriget had not shown a "heightened" relationship with the Church, such as serving as an altar boy, that would separate his standing from that of a typical parishioner. The court also found no evidence the diocese sponsored or knew about Father O'Sullivan's visits to the family's home and no record of complaints against him before or after Leriget came forward in 2019.

Zeale News reached out to officials at the Diocese of Boise for additional comment but did not receive a response by the time of publication. 

The justices found that examining whether such a relationship of trust existed more broadly would risk improper interference with the Church's religious practices, a violation of the First Amendment's free exercise clause.

The case is among several clergy sexual abuse lawsuits that have moved through Idaho courts in recent years as survivors have come forward decades after the alleged incidents.