"There were people who thought he was a great priest, that they really liked him, he looked like a priest, he walked like a priest, he could talk like a priest all the way to the very end," Guevara added.
But Mena couldn't fool what Guevara called the "professional Church ladies." It was a feast day with particular Mass parts, and Mena just wasn't getting it right, he said.
"It was a complicated Mass that some of the real professional church ladies have memorized, and literally the jig was all up," Guevara said.
"He was screwing up and everybody was like, what's going on here?"
Within hours, phone calls were being made, and the archdiocese was officially alerted of Mena's suspicious activities. Soon after, the archdiocese reported him to the police.
"They were collecting information and they were very transparent about it," Guevara said. "They contacted the police department really quickly and provided us with everything we needed, so it was a really good partnership with us and them."
It seems that Mena may even be a repeat offender – Guevara said that according to Archdiocesan documents, there were issues with Mena as far back as the 1990s. His name has been on a list of unauthorized priests and deacons since 2008, when the record was started. The current investigation is only focusing on his recent alleged transgressions.
It's important to note that Mena was arrested because he was allegedly masquerading as a Roman Catholic priest, Guevara said. A defrocked or retired priest could theoretically start up their own "storefront church" with a ministry certificate from the internet, but he said Mena's offense is specifically that he pretended to be a Roman Catholic, sacrament-distributing priest.
The archdiocese has already reimbursed some of Mena's alleged victims, and more could be reimbursed at the conclusion of the case. Because of the nature of the ongoing criminal investigation, the archdiocese could not provide much further comment, but asked that anyone with additional information come forward.
"We are grateful to the Los Angeles Police Department for working to ensure that Erwin Mena was brought to justice. Our prayers go out to all the victims of his scam. The Archdiocese of Los Angeles is committed to providing pastoral care and sacramental support to the victims and others impacted by this situation," the Archdiocese said in a statement.
"If anyone in the Archdiocese has any questions regarding the validity of any priest's credentials, or the credentials of any employee of the Archdiocese of Los Angeles, please call the Archdiocese Catholic Center, at (213) 637-7000."