The blaze broke out at St. John Vianney in the 1300 block of Turnbull Canyon Road shortly after midnight. The priest, who was asleep in the rectory adjacent to the church, realized the building was on fire when he heard loud popping noises.
The church was fully engulfed when fire crews and arson investigators arrived on scene. Authorities said the fire was raging hottest in the auditorium of the church. They said the wooden pew inside the auditorium accelerated the blaze.
It took firefighters several hours to get the fire under control. Crews were able to stop the fire from spreading to the rectory and also saved precious relics from inside the church.
The church was completely destroyed with damage estimates at approximately $9 million.
"We were here as original parishioners. We spent hours building this church and having fund raisers," said parishioner Anita Dunbar.
"Keeping the faith, we'll build it again," said another parishioner.
No injuries were reported.
No information was released on the identity of the suspect.
The Arson and Explosives Detail of the Los Angeles County Sheriff's Department is leading the investigation.
If you have any information regarding the fire, you're urged to contact arson investigators at (323) 881-7500.