The suspected arsonist accused of setting a 34,000-acre wildfire east of Los Angeles may have started other fires, authorities say.

Justin Wayne Halstenberg was charged Tuesday following a San Bernardino Sheriff’s Department investigation into the Line Fire, which has torched an area about half the size of Queens, New York, since it started last week.

Law enforcement found evidence including an “incendiary device” in Halstenberg’s home and vehicle, the San Bernardino Sheriff’s Department said Wednesday.

“It is my belief that as time goes on … that we will actually find out the suspect may have been responsible for other fires,” said Sheriff Shannon D. Dicus.

The arrest came after a joint investigation with Cal Fire detectives that used a combination of forensic evidence of the fire, automatic license plate readers, and witness statements to eventually identify Halstenberg and his vehicle, a white pickup truck.

“Highland Station detectives, in collaboration with Cal Fire investigators, identified Justin Wayne Halstenberg as the suspect who started a fire in the area of Baseline Road and Alpin Street in the city of Highland, also known as the Line Fire, on September 5, 2024,” the sheriff’s office said.

Halstenberg, a resident of Norco, Calif., has been a delivery driver for FedEx since February 2023, according to his LinkedIn profile.

He previously worked as a letter carrier for the US Postal Service and was a meat clerk for grocery store chain Stater Bros. Markets.

The 34-year-old suspect was slapped with arson of an inhabited structure, arson of forest land and possession of flammable material charges, jail records viewed by The Post showed.

He is being held at San Bernardino’s Central Detention Center on $80,000 bail.

Police did not reveal how Halstenberg allegedly started the inferno.

He is scheduled to appear in court at 12:30 p.m. Thursday.

The Line Fire started around 6:33 p.m. Sept. 5 and has destroyed 34,289 acres inside the San Bernardino National Forest. The blaze was only 14 percent contained as of Wednesday morning, according to the California Fire website.

Residents along the southern edge of Big Bear Lake were told to leave the area, a popular destination for anglers, bikers and hikers.

The blaze had charred vast areas of grass and brush and blanketed the area with a thick cloud of dark smoke.

The acrid air prompted several districts in the area to close schools through the end of the week because of safety concerns.

Three firefighters have been injured since the blaze was reported Thursday, state fire managers said.

Mandatory evacuation orders have been issued for areas north and east of the fire including popular ski town Big Bear.

Evacuation warnings were given to the communities directly south of the national forest, which included parts of the city of Highland.

Gov. Gavin Newsom declared a state of emergency Saturday and deployed the National Guard to assist in the evacuations.

Over 2,800 personnel have been allocated to fighting the fire as 65,600 structures are threatened.

Wildfires have broken out across the Golden State during a triple-digit heat wave that finally broke Wednesday.

Officials hope lower temperatures expected for later in the week will moderate the fire.

Just over 30 miles west on the San Bernardino-Los Angeles County line, the Bridge Fire started on Sept. 8 and has burned 46,727 acres (73 square miles, a little larger than Brooklyn).

With Post wires