Church officials say a pair of nuns embezzled a “substantial” amount of money from the Southern California Catholic school where they worked for decades and used it to pay for gambling trips to Las Vegas casinos.

Adrian Alarcon, a spokeswoman for the Archdiocese of Los Angeles, said Monday the embezzlement appears to have gone on for about 10 years.

During that time Sister Mary Margaret Kreuper was principal of St. James Catholic School in Torrance, which is overseen by the St. James church in Redondo Beach. Sister Lana Chang taught eighth grade there. Both retired earlier this year.

Sister Mary Margaret retired in June after 28 years as principal of the K-8 school, which serves students from Torrance and Redondo Beach. A routine audit upon her retirement raised “several red flags” of “checks being cashed into different accounts,” said Alarcon. The amount is thought to be in the range of $500,000, but an investigation is underway to determine the full amount, Alarcon said.

Chang taught the eighth grade for about 20 years and was the school’s vice principal for the past several years, the Los Angeles Times reported. She also retired at the end of the 2017-2018 school year.

The church and archdiocese chose not to press for criminal charges against the sisters, Monsignor Michael Meyers said. Instead, they plan to “address the situation internally through the investigation, restitution and sanctions on the sisters.”

“Sister Mary Margaret and Sister Lana have expressed to me and asked that I convey to you, the deep remorse they each feel for their actions and ask for your forgiveness and prayers,” Meyers wrote in the letter. “They and their Order pray that you have not lost trust or faith in the educators and administrators of the school.”

No one else was implicated in the alleged theft, the letter reads. The sisters’ order, the Sisters of St. Joseph of Carondelet, is working with the Los Angeles Archdiocese to “arrange for full restitution for the benefit of the School of the funds that are found to have been misappropriated,” the letter reads.

The nuns are still with the order, which has promised the Archdiocese sanctions in a form to be determined, Alarcon.

The order said on its website that the sisters “confirmed the misappropriation of funds and have cooperated in the investigation.”

“Our community is concerned and saddened by this situation and regret any injury to our long relationship with the families of the school. The Sisters of St. Joseph both desire and intend to make complete restitution to St. James School.”

The monsignor’s letter reads: “I want to assure you that the investigation has disclosed that, notwithstanding this misappropriation, no student or program at St. James has suffered any loss of educational resources, opportunities, or innovations. In sum, the education of your children has not and will not be affected by these events.

“At our School, we have initiated additional procedures and oversight policies for financial management and reporting responsibilities. I appreciate the efforts of the School staff to date and will continue to work with them directly on these issues.”