The surveillance video showed a man walking in the cemetery of the San Gabriel Mission with a deliberate gait, the priest said, as if he was unworried about being caught for what he was about to do.
Methodically, he destroyed two tall granite statues, including a tombstone, depicting Jesus. He used a garden hose as a lasso in an attempt to bring one of them down.
In the early-morning darkness Wednesday, the man took his time, said Father Manuel "Tony" Diaz. He took a 5-pound rock and smashed one of the statues until it was left without a head or arms.
In dollars and cents alone, the damage was costly: at least $50,000.
But the priest said the greater cost was the deep sadness the vandalism left in its wake, not only for those who were buried at the cemetery, but also for the Catholic community that recognize the historical significance of the mission.
"You take it very personal," Diaz said. "It really touches all sensibilities."
As of Sunday, no arrests in the case had been made.
San Gabriel Mission was one of only two missions that Father Junipero Serra had called home. This month, Pope Francis announced that the founder of nine California missions, including the San Gabriel Mission, would be canonized.
Records show that Serra performed confirmations and baptisms when he lived in the San Gabriel Mission, established in 1771.
Diaz said he doesn't know why the cemetery or the tombstones were targeted. There were no clues left behind, no graffiti scrawl or note to explain the man's actions.
Serra's pending canonization is not without controversy. Serra has been praised for the string of missions he and his Franciscan order established that provided an origin story for California. Supporters say Serra was an advocate of Native Americans, sparring with governors and military commanders in New Spain over their treatment.
But critics have pilloried Serra as an agent of Spanish oppression and genocide.
Diaz does not believe the vandalism had anything to do with Serra, though "it has crossed our minds."
"Whenever our mission is in the news, we do attract more attention," he added.
Police likewise say they don't know what provoked the man to destroy the grave markers.
"This is a tragic and despicable incident, and whoever is responsible for this should be ashamed of their actions and brought to justice," San Gabriel Police Chief David A. Lawton said.
The Archdiocese of Los Angeles said the man was probably "angry and deeply troubled."
"We hope he comes forward," archdiocese spokeswoman Monica Valencia said. "We are a forgiving community and want to continue to create a peaceful and sacred environment at the cemetery."
The cemetery has continued to perform burials, although all plots have been sold.
In the past there have been such incidents as teens scaling the mission's cemetery walls to topple flowers and small ornaments.
But none of the previous acts of vandalism at the San Gabriel Mission's cemetery compared to last week's, Diaz said.
The man destroyed a nearly 5-foot-tall tombstone and 7-foot-tall ornamental statue that stands in the center of the cemetery, welcoming visitors.
Last February, Valencia said, a surveillance camera filmed another person, in a hooded sweatshirt, breaking statues and vases at an altar at St. Patrick's chapel in North Hollywood.