Four men from the Los Angeles area were arrested in connection with a series of diesel fuel thefts targeting commercial trucks across Ventura County, authorities said.

The arrests followed a weeks-long investigation into thefts in Oxnard, Camarillo and Thousand Oaks that resulted in an estimated $3,330 in losses, according to the Ventura County Sheriff’s Office.

The suspects were identified as Los Angeles County residents, Alfonso Vargas, 52; Alfonso Vargas Jr., 33; Gilbert Flores, 37; and Miguel Cruz, 38. All four are have extensive criminal histories, according to sheriff’s officials.

The investigation began Sept. 18, when deputies responded to a reported fuel theft at Tri County Transportation, a commercial truck and semi-trailer storage yard in an unincorporated area of Oxnard.

The victim reported that approximately 70 gallons of diesel fuel had been siphoned from his semi-truck.

Detectives reviewed surveillance footage showing a vehicle scouting the property and inspecting parked trucks. Minutes later, a large white Ford Econoline-style van arrived, and several suspects exited the vehicle and siphoned fuel from a truck, authorities said.

Although investigators initially could not identify the vehicles, the Sheriff’s Office’s Flock automated license plate reader system helped detectives identify both vehicles and link them to other diesel thefts throughout the county.

Working with the Sheriff’s Office Crime Analysis Unit, investigators identified four additional thefts in Camarillo and Thousand Oaks dating to August and noticed a similar patterson where one vehicle looked out for the suspects in Ford with the fuel-siphoning equipment. 

Authorities said approximately 315 gallons of diesel fuel were stolen in those four incidents. In one case, a suspect broke a locking fuel cap to access the fuel.

On Oct. 13, detectives received information that the suspects were again scouting locations in Ventura County, particularly in Thousand Oaks.

Detectives from the Sheriff’s Office Headquarters station and the West County Special Enforcement Unit conducted surveillance and observed the driver of a GMC Sierra acting as a lookout while suspects in the Ford van siphoned diesel from a Freightliner truck parked at a local business, officials said.

After witnessing the theft, detectives followed both vehicles and conducted simultaneous traffic stops at separate locations, where they were able to detain the four suspects.

A search of the van revealed two fuel tanks with a capacity of 1,200 gallons each, along with pumping equipment, according to investigators.

All four suspects were arrested and booked into the Ventura County Pre-Trial Detention Facility on suspicion of conspiracy to commit theft, with additional charges pending.