The three-feet hate symbols were created by pouring a corrosive substance onto the synthetic grass either late Wednesday or early Thursday.
The same person or group may also be responsible for burning two other swastikas on the pavement about a block away, police said.
The San Dimas home belongs to 69-year-old Ted Ferris, who is not Jewish.
“My first reaction?” Ferris told the Times. “If I knew who did it, I’d choke ‘em — and that’s [saying it] politely.”
Because he isn’t Jewish, the Los Angeles County Sheriff’s Department isn’t investigating the incident as a hate crime, but there is a felony vandalism report.
Sergeant Peter Shupe told the Times that he chalked it up to teenagers “just being little jerks.”
This story "Two Swastikas Burned Into Lawn In Los Angeles" was written by Alyssa Fisher.