LOS ANGELES (AP) — A Claremont man has pleaded not guilty to federal charges that he sent threatening letters containing a powdery substance to Department of Children and Family Services offices throughout Southern California and to the Los Angeles County Children’s Courthouse.

U.S. attorney’s office spokesman Thom Mrozek says 48-year-old Martin Calvin Yarbrough Jr. was released on $25,000 bail Friday following his arraignment on 13 counts of making threats and
hoaxes.

READ MORE: Residents Say Strong Stench In Carson Keeps Getting Stronger

Prosecutors say Yarbrough sent the letters to eight DCFS offices and to the Monterey Park courthouse between November 2008 and May 2010. Each letter contained either a white powdery substance or a
bluish granular substance that was determined to be a chemical poison.

READ MORE: Man Suspected Of Stealing Truck Taken Into Custody Following Pursuit

Mrozek says there are no reports of anyone being sickened by the substances.

Yarbrough did not return a phone message.

MORE NEWS: LA Firefighters Respond To Fire At Suspected Marijuana Grow Operation In Canoga Park

(© Copyright 2011 The Associated Press. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)