The United States postal service is looking at another group of threatening letters.It's the second round of threats to area post offices this year.Postal Inspection Officer Jeff Long says none of the seven offices that received letters back on February 5th are affected by the new threats.He declined to identify which offices are targeted because of the investigation, but he did say they have all been notified.Long also says anyone with information should call 1-877-876-2455 option number two and ask for a Saint Paul Field Officer Duty Inspector.Information leading to an arrest and conviction of those responsible for mailing the letters could be worth up to 100-thousand dollars.