A nun involved in a legal dispute with Katy Perry over an L.A. convent is appealing to Pope Francis in an apparent effort to block the sale of the property to the pop singer.

Sister Rita Callanan, one of the few surviving members of the Order of the Immaculate Heart of the Blessed Virgin Mary in Los Angeles, is calling on the Vatican's highest authority to intervene in the legal dispute over the sale of a convent in the Los Feliz area.

Perry had signed a deal with the Archdiocese of Los Angeles, headed by Archbishop Jose Gomez, to buy the property for $14.5 million. But Callanan and her fellow Sister Catherine Rose Holzman opposed the sale to the pop singer, claiming that the convent had been under the ownership of the Order for 45 years and that it was their right to sell it.

Callanan recently sent a letter to Pope Francis in the hopes that he would review the case and forward it to Rome's highest court, the Signatora.

Last month, Holzman died unexpectedly in court, leaving Callanan to fight the court battle alone. The 80-year-old nun said doctors and friends have advised her to drop the case for health reasons, but she said that Holzman's death had motivated her to keep fighting.

"They'll have to kill me first if they want to keep me quiet," the nun said, according to Fox News, adding, "I am asking Pope Francis to intercede."

In her letter to the Pope, Callanan noted that the nuns "were promised that we would always be taken care of by the archdiocese and that we would live out the rest of our lives at our convent. After we are all gone, the Archbishop would inherit our property ... Archbishop Gomez has broken these promises to us."

"He tried to sell our convent without our approval to a person whom we do not support. It is the pop star Katy Perry. We do not agree with her lifestyle that has strayed far from any faith ... At the end of our lives, we find ourselves fighting for justice and for what is right," the letter stated, as reported by Fox News.

The nuns attempted to sell the property to entrepreneur Dana Hollister, who was planning to turn it into a boutique hotel. But Los Angeles County Superior Court Judge Stephanie Bowick had ruled that the nuns' deal with Hollister was improper because they were not authorized to dispose of the property and the sale was not properly documented.

Shortly after Holzman's death, Callanan said she had been struggling to make ends meet because all her savings had been used up in the legal dispute. A GoFundMe page has been set up to raise money to help pay for her legal costs.