U.S. law enforcement agencies in Dubuque, Iowa, on April 25 arrested a man they believe to be "The Bishop," a suspect who has sent improvised explosive devices (IEDs) through the mail. Authorities have identified the suspect as 42-year-old former postal worker John Patrick Tomkins.

The Bishop first appeared on Stratfor's radar screen in 2005 when he was sending anonymous, threatening letters to various financial services companies. The letters demanded that the targeted companies -- financial firms based in the U.S. Midwest -- take action to manipulate specific stocks to a predetermined price, frequently $6.66. The Bishop eventually escalated to sending IEDs through the mail to these companies. The IEDs were complete but intentionally not fully assembled.

According Stratfor sources, analyzing and following stock trading records led U.S. Postal Service investigators to Tomkins. Also, a photograph included in an Oct. 25, 2005, threat letter showed the window of the vehicle from which the photograph was taken. The vehicle was identified as a four-door Chevrolet Lumina. Authorities observed Tomkins driving a red 1993 Chevrolet Lumina. The interior of the vehicle appears to match the vehicle shown in the photograph.

After authorities surveilled the suspect for a lengthy period and built their case, search and arrest warrants were executed. Because of the nature of The Bishop's alleged crimes -- sending IEDs through the mail -- the possibility that he could detonate an IED while being arrested was a major safety concern.

After the arrest warrant was served, authorities in Dubuque evacuated part of an apartment complex when a bomb-sniffing dog stopped at a storage locker connected to the suspect. The apartment complex is located about a mile from the suspect's residence on the west side of town.

Tomkins has been described as a machinist who is married and has three children. This does not fit the original criminal profile compiled by the FBI.

The complaint, filed by the U.S. Postal Inspection Service in U.S. District Court in Northern Illinois, details the evidence allegedly tying Tomkins to the crimes, such as his stock transactions in the companies The Bishop was focused on, credit card and ATM receipts linking him to locations where letters were mailed, handwriting comparisons and credit card receipts showing that he bought materials at a hardware store similar to the components used in constructing the IEDs.

Authorities should be able to locate a large amount of additional evidence from their searches of Tomkins' home, storage space, vehicle and computer.