Associated Press Writer

CHEYENNE, Wyo. - Alert workers at the state's mail processing center intercepted a suspicious letter Friday that appeared rigged with matches set to ignite when opened.

A letter was addressed to Gov. Dave Freudenthal and had a return address from the same maximum-security prison in Nevada that was the apparent source of other suspicious letters sent to other governors nationwide, according to Lara Azar, Freudenthal's press secretary.

The state's Central Mail Office is located outside the Capitol grounds in Cheyenne.

Employees there noticed the business-sized envelope matching descriptions provided in a nationwide alert and determined it had suspicious objects inside.

The letter was not opened, and a specially designed robot removed it from the mail center. The U.S. Postal Inspection Service has taken control of the letter for further investigation.

The mail center was evacuated, but workers were allowed to return once the letter had been removed.

"It's unfortunate that this kind of event has become part of the world we live in, but I do want to commend everyone with Central Mail, the Office of Homeland Security and law enforcement for making sure what could have been difficult circumstances were handled with professionalism and the kind of dispatch we've come to expect from people in Wyoming," Freudenthal said in a statement.

Similar letters have been sent to states around the country. In Montana, two floors of the Capitol wing containing the governor's office were evacuated for about two hours Thursday.

There were no reports of injuries.

All were postmarked from the Ely State Prison in Ely, Nev., officials said.

Mail addressed to the governor or his staff in Wyoming is inspected before it reaches the Capitol office, Azar said.