An Oklahoma man has been arrested for allegedly mailing a suspicious package that contained explosives to a sheriff in Arizona last year, authorities said Tuesday.
Gregory Lynn Shrader, 55, was taken into custody last Thursday after FBI agents and U.S. Postal Service inspectors served a search warrant at his home in Jay, Okla.
According to a nine-page criminal complaint filed in a U.S. District Court in Arizona, Shrader is accused of mailing a homemade bomb to Maricopa County Sheriff Joe Arpaio last April 11.
The package was discovered in a USPS collection-box unit on Highway 180 in Flagstaff.
Authorities originally said the package appeared to contain an improvised explosive device that could have led to serious injuries or death if it was opened, but investigators later determined the device lacked a bridge wire and was inoperable.
Authorities, however, said the parcel contained smokeless black powder and could have exploded or ignited in a flash fire.
The criminal complaint said there was probable cause to believe that Shrader used the mails to "make a threat to injure, kill or intimidate Joe Arpaio by means of an explosive."
It was unclear Tuesday if Shrader had lawyer.
"It's good to have the guy off the street," Arpaio said Tuesday afternoon. "I'm grateful that the feds did a good job. The postal service and the FBI have been working on this for almost a year, and they got the guy."
Arpaio, the self-proclaimed "toughest sheriff in America," has had a security detail for years and said he regularly receives threats including "at least 12 in the last year."
The 81-year-old Arpaio has been sheriff of Arizona's most populous county since 1993 and is known nationally for his strict treatment of jail inmates and cracking down on illegal immigration.
But Arpaio said the explosive package case was especially troubling "because it could have caused havoc if it was opened up and been dangerous for me and people around me."
A postal employee in Flagstaff saw that the suspicious package was addressed to Arpaio at his Phoenix office and had a return address for a post office box in California.
The employee also noticed that the parcel had excessive stamps postage and the address label was typewritten.
Postal inspectors looked at the package and saw silver grain-like material spilling out from the seams that was later determined to be explosive smokeless powder.
Flagstaff police used a robot equipped with X-rays to examine the parcel and determine it also had wires, a battery and a pressure-release switch attached to its lid.
Fearing it was an operational improvised explosive device, law enforcement officials disabled it with a water cannon.
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.