AMES, Iowa (AP) -

A suspicious substance found in a package sent to the Iowa State University student newspaper in Ames turned out to be harmless.

The Des Moines Register reports that Jay Knox of the U.S. Postal Inspection Service said Wednesday that the substance was just paper residue.

The Iowa State Daily's office was evacuated Wednesday during the investigation.

The newspaper editor, Stephen Koenigsfeld, says the package return address said it was from Robert Alberg. A Washington state man with that name was sent to prison in 2005 for violating parole by trying to manufacture the poison ricin.