(Eugene, OR)  --  Oregon State Police say they've released a person of interest in connection with suspicious mail that was sent to government offices across the state.  The man was interviewed yesterday in Eugene, but no arrests were made.  Grant County Sheriff Glenn Palmer said he had a negative reaction from opening one of the suspicious letters Monday, but officials say all of the suspicious mail has tested negative for toxic substances.  Police say the letters contained a message that was difficult to understand, but there's no word on what the message said.