The top Republican on the House panel that oversees the security of the Capitol says "there was obviously a screw up" in how U.S. Capitol Police handled the impoundment of a truck later found to contain a crude explosive device.

Lawmakers "will hold the people accountable" for the apparent security flub, U.S. Rep. Dan Lungren, R-Calif., said in a phone interview with FOX News Radio.

Capitol police arrested Michael Gorbey near the Capitol in January and impounded his pickup truck after he was seen carrying a loaded shotgun.

But The Washington Post reported Wednesday that the explosive device was stowed undetected in the truck for weeks on government property.

Capitol police spokeswoman Kimberly Schneider told FOX News that the article was "inaccurate," in that there was not a "single" explosive device -- rather she said there were a number of materials inside, ranging from wires to ammunition, that could be used to make a bomb.

Regardless, Lungren complained about the amount of time it took to get a warrant.

The truck was towed and stored at the Government Printing Office garage, located just a few blocks from the Capitol and the bustling Union Station.

The Capitol police park many cruisers in their fleet at the GPO, and the truck remained there for three weeks while police obtained a search warrant to go through the vehicle. They made the request for the warrant Jan. 19 and received it Feb. 7.

"If a search warrant were required, it should have been obtained immediately," Lungren said.

He presumes police didn't see anything in their initial inspection that called for urgency, but he suggested that doesn't excuse moving a vehicle containing a bomb into a government building.

Lungren said he wants to sit down soon behind closed doors with police officials to determine what went wrong. He did not call for a public hearing.

"You just can't say it was a screw-up and move on," Lungren said. "Someone has to be held accountable."

The chairman of the full House committee that oversees security at the Capitol, U.S. Rep. Robert Brady, D-Pa., had no comment.