PHOENIX (AP) -- An Oklahoma man has pleaded not guilty to charges that he mailed an inoperable homemade bomb nearly a year ago to Maricopa County Sheriff Joe Arpaio.
Gregory Lynn Shrader, 55, of Jay, Okla., entered the not guilty plea on Friday in federal court in Phoenix.
Debra Massey with the U.S. Attorney's office in Phoenix said Shrader was arrested at his home on Thursday, March 6 after a federal criminal complaint was served.
Investigators say the bomb was discovered last April at mail collection-box unit in Flagstaff and was made of smokeless powder, wires, a battery and a pressure-release switch attached to its lid.
Authorities eventually determined the bomb was inoperable, though black power inside the parcel could have exploded or ignited in a flash fire.
Police disabled the bomb.
Authorities contacted the man whose name was on the return address, and he denied sending the package. But he told investigators that he believed his former business partner was trying to frame him and that led them to Shrader.
The FBI and postal officials said they recovered a document of an image that closely resembles the return address of the suspicious parcel at Shrader's home last week.
Authorities said they tracked Shrader's bank activity last April on a car trip from Oklahoma to Flagstaff along with security footage at gasoline stations along the way and at the Grand Canyon's south entrance.
FBI agents also interviewed a woman who said she drove with Shrader to northern Arizona and allegedly saw him place the parcel into the mail box wearing surgical-type gloves.