EAST TEXAS (KYTX) -- The FBI and U.S. Postal Service are offering a $150,000 reward for help in catching those responsible for sending hundreds of letters containing a white powdery substance.
North Texas has seen at least 11 scares in the past week.
The FBI says the white powder is non-hazardous and in many of the cases it's cornstarch. The letters have been sent to schools, government agencies, and churches.
"He's working hard to conceal his methods," Dallas FBI Special Agent Kevin Kolbye said. "We do not have any fingerprints on these envelopes."
The FBI says call 911 if you receive a letter containing white powder.