According to law enforcement officials, they have been warning about an increase in catalytic converter thefts in Altadena.
They occur early in the mornings and most of the vehicles are parked curbside, according to the A County Sheriff Department.
The suspects are targeting Toyota Prius's and Honda's.
Authorities believe that they are being stolen due to the high amount of titanium.
Once they steal the part, they are selling them to scrap yards for hundreds of dollars.