OKLAHOMA CITY — Authorities were searching Wednesday for two inmates who may be armed after overpowering two transport officers and stealing their van in northwestern Oklahoma.

Andrew Foy, 32, and Darren Walp, 37, were being transported to Wyoming and Kansas to face charges for nonviolent offenses when they stole the van early Tuesday north of Fairview, a small city about 80 miles (129 kilometers) northwest of Oklahoma City.

The investigation shifted Wednesday to a neighboring county after some of the inmates’ personal belongings were found, said Major County Sheriff Steve Randolph. Investigators believe the inmates are now driving a truck stolen from an employee of a nearby oilfield company.

“We have trash on the highway from the inmates … clothing, court papers, personal property,” Randolph said.

The van was found about 13 miles (21 kilometers) from where it was stolen. Inside, investigators found a transport guard’s belt that included an empty gun holster. The sheriff said the guard claimed he didn’t have gun, but “we’re not sure he was telling the truth.”

The men were being transported by Inmate Services Corporation. Officials with the West Memphis, Arkansas-based company did not return a phone message from The Associated Press seeking comment.

Foy, who is from Cheyenne, Wyoming, was wanted on a felony failure to appear in court warrant on charges that include burglary, theft and fraud. He was being extradited from Doylestown, Pennsylvania, where he was arrested on the Wyoming charge, according to Capt. Michael Sorenson of the Laramie County Sheriff’s office in Wyoming.

Walp, whose address is listed as McLeansboro, Illinois, was wanted for failure to appear in court on an auto theft charge in Liberal, Kansas, when he was arrested in Tennessee, according to Gene Ward, undersheriff in Kansas’ Seward County. He said Walp has worked as a truck driver in the cattle industry, but has no known ties to Kansas.

“No family here that we know of,” Ward said. “I don’t know why he would come this way.”

The inmates have lengthy criminal histories involving burglary, theft and property crimes, but no violent crime convictions, according to the sheriff’s offices. The sheriff’s officials also said they weren’t aware of any previous problems with the transport company.