WASHINGTON - Word to the wise: Be careful what you send to the U.S. Capitol.

A package addressed to Congressman Tim Walz's office forced the evacuation of a Capitol office building Wednesday afternoon after police determined it to be suspicious. The package contained a metal box and an unidentified medal, said FBI Washington Field Office spokeswoman Katherine Schweit.

Capitol Police called the FBI, who X-rayed the package and transported it in a reinforced containment vessel to the Quantico Marine Corps Base in Virginia about an hour away. At the base, bomb experts used a "high-velocity water cannon" to dismantle it, Schweit said.

"If it was a high-powered bomb it would go off -- potentially," Schweit said of the process. "But it would be in a place where that would be OK."

The package was determined to be harmless. The person who sent it was identified and contacted, but no charges have been filed. The entire episode took about eight hours.

Walz spokeswoman Sara Severs would not comment on the details of the package but said Walz wanted to thank the Capitol Police for their response.

The News & Messenger newspaper reported that the package was initially viewed as suspicious because of a "chemical stain."

A Capitol Police spokeswoman would not comment further on the package, but said the building was evacuated because its contents could not be easily identified.

ERIC ROPER