(AP) — A 49-year-old Alabama man serving time for sending anthrax hoax letters has been convicted of sending similar letters from a federal prison in Louisiana.
The conviction could add up to 20 years to Clifton Lamar Dodd's prison time.
He was sentenced to a total of more than 15 years in two earlier cases.
Prosecutors said he was trying to make trouble for other inmates by sending powder in letters to the U.S. Senate in 2016.
A federal jury in Lafayette convicted him Thursday on four counts of mailing the hoax letters.
He pleaded guilty in 2011 to 23 counts of mailing such letters and was convicted in 2013 on charges that included mailing a hoax letter and death threats.
