Authorities are investigating a suspicious mailing — initially thought to be a bomb — that was sent to bestselling author John Grisham (search) at his farm in Albemarle County.

"It appeared to be a potentially explosive device," said Lee Catlin, a spokeswoman for the county. "But a state police evaluation determined it was not a functional explosive device."

County fire marshal Bob Lowry said Tuesday the large envelope was placed in Grisham's mailbox Saturday but was not delivered by the U.S. Postal Service.

The envelope was taken into the house with the rest of the mail and someone in the Grisham house noticed "something suspicious" through a small opening in the envelope, Catlin said. Grisham called police.

The fire marshal's office and county police responded and examined the package, then called the Virginia State Police. The state police responded with a bomb dog and several technicians from the bomb squad.

Grisham's lawyer, Patricia McGraw, said Grisham "has no idea who's behind this and will have no further comment."