The Associated Press

LOUISVILLE, Ky. (AP) - A military contractor under investigation on allegations he overbilled and did faulty repair work on Navy and Army aircraft has been charged with threatening to kill witnesses in the case, according to a complaint unsealed Thursday.

Keith E. Shaw, owner of Shaw Aero in Louisville, traveled to Tennessee to buy explosives as part of a plot to blow up his former business partner's plane, according to an affidavit filed in federal court by an investigator for the U.S. Department of Defense.

Shaw was arrested Wednesday by deputy U.S. marshals. His attorney, Thomas Clay of Louisville, did not immediately return a message seeking comment.

The affidavit written by DOD Criminal Investigator Jared Camper was unsealed Thursday by U.S. Magistrate Judge Dave Whalin.

Camper said the department has been investigating Shaw for three years for allegedly defective repair work on Navy fighter jets and Navy Seahawk and Army Blackhawk helicopters. He has not been charged in the contracting investigation.

The DOD investigation also focuses on allegations that Shaw billed for work not done on the LN-93 Laser Navigation System, which is used on the C-130 Hercules transport aircraft. Camper wrote that investigators served two search warrants on Aug. 4 and Aug 6 related to that allegation.

Camper said Shaw is also accused of telling employees to fraudulently repair solid state gyros, which are used to measure and maintain stability in Blackhawk and Seahawk helicopters. Both allegations stem from an investigation that Shaw did defective repair work on the inertial navigation system for F-5 jets used by the Navy to train pilots.

Camper wrote that former business partner Dean Dickinson and ex-employee Andrew Brown, along with four confidential informants, provided information about Shaw during the investigation.

At least three confidential informants said Shaw repeatedly talked about killing Dickinson, becoming more serious over time, Camper wrote.

One of the plots involved putting high-powered explosives inside the wings of Dickinson's aircraft, then attacking pressure switches that would cause an explosion once the plane reached a certain altitude, Camper wrote. One informant bought the switches at a hardware store and said Shaw traveled to Tennessee to get the explosives, Camper wrote.

Shaw relayed this plot to another confidential informant, laying out how he would implant the explosives and switches in Dickinson's plane while it was parked at the unguarded airstrip at Kentucky Lake, in western Kentucky, Camper wrote.

A fourth confidential informant told Camper that in December 2008 Shaw offered him $100,000 to kill Dickinson and Brown and delivered him a .308 sniper rifle, Camper wrote.

Federal authorities seized the sniper rifle during a search on Aug. 24.

Dickinson declined to comment to The Associated Press.