FBI, U.S. Postal Services offers $150,000 for help in white powder case

The U.S. Federal Bureau of Investigation and U.S. Postal Service recently announced the establishment of a $150,000 reward for information that leads them to the mailer of at least 380 white powder threats.

Since 2008, a series of typewritten letters containing a white powder and cryptic messages about the FBI, CIA, al-Qaeda and Nazis have been sent from North Texas. The letters have been mailed to schools, churches and businesses in North Texas and around the world, according to NBC.

According to FBI agents and U.S. postal inspectors, some of the more recent letters have contained references to the cartoon dog Scooby Doo.

"Those who know or have encountered this person may consider him odd or eccentric," Kevin Kolbye, the acting special agent in charge of the FBI's Dallas office, said, NBC reports.

Agents revealed details about the 13 batches of letters at a recent news conference.

"We need to find this person before he sends his next batch," Kolbye said, NBC reports. "This person is disrupting people's lives."

FBI experts said they believe the subject to be at least over the age of 30 and to have a history of what they described as mental challenges. They also believe he has a limited mastery of English because of a profusion of punctuation and spelling errors.