Authorities said two men used chainsaws to dig out large pieces of wood from the cedar base of a bridge in Jefferson County, Washington, and were arrested on felony last Friday.

Officials said they suspected that the two planned to sell the timber on the black market.

After a pair of hunters in Jefferson County heard the sound of a chainsaw and contacted the Washington State Department of Natural Resources, Troy Crandall and Jose Salinas were booked to enter the Jefferson County Jail.

"Police Officer Alan Nelson was already in the area and found two people cut large pieces from the cedar logs that make up the bottom of the bridge," the department said in a tweet on Thursday. "Cedar blocks will be sold on the black market for factory owners to turn them into milkshakes and shingles."

Although these people did not tell the authorities that they planned to sell the wood, Kenny Ocker, a spokesperson for the Washington State Department of Natural Resources, said that depending on the type of wood and the way they cut it, this is obvious.

"The beam of that bridge is western red cedar, and there are factories in that general area that use ton-level cedar," he said.

Authorities said the area was behind a locked door, but the people allegedly broke the door lock to enter it.

Oak said his agency had conducted a preliminary inspection of the bridge, but kept it closed while determining what measures needed to be taken to ensure its safety.

The department said in a tweet: "This is very dangerous for our employees working in the woods and the public."

Oak said the incident in Jefferson County, west of Seattle, was not the first such arrest.

"This is not the first time," he said. However, he added: “We don’t go out once a week and use a chain saw to look for people under the bridge.”

Elizabeth Chuck is a reporter for NBC News, focusing on health and mental health, especially issues affecting women and children.