Letters containing suspicious powder top 30

WASHINGTON — The number of governors' offices receiving letters containing suspicious powder has topped 30.

The letters, all postmarked in Texas, began arriving at governors' offices — including Missouri's — across the country on Monday. So far, field tests have indicated the powder to be harmless, though further testing is under way, the FBI said Friday.

"It's likely there will be more" letters, FBI special agent Richard Kolko said in a statement.

The Postal Inspection Service, which is working with the FBI, noted that sending hoax letters can result in up to five years in prison.

States where the letters have been received, according to information provided by the FBI, are Alabama, Alaska, Arizona, Colorado, Connecticut, Florida, Georgia, Hawaii, Idaho, Indiana, Iowa, Kansas, Maine, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, North Carolina, North Dakota, Oklahoma, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, West Virginia and Wyoming, plus Puerto Rico and the Virgin Islands.