FBI investigating Houston anthrax letters

Federal agents have reported that they are pursuing leads to discover who mailed envelopes full of white powder to 17 independent school districts in Houston, Texas.

Officials told Examiner.com that 13 schools called local police and Hazmat teams last week when the letters with the white powder arrived. Officials reported four more envelopes arrived at different schools this week.

The FBI has taken the lead in the investigation while officials with the U.S. Postal Inspection Services have charted out plans to try to intercept any other suspicious mail before it reaches any schools.

“The U.S. Postal Inspection Services takes investigations relating to 'hoax' mailings very seriously,” an unnamed spokesman told Examiner.com.

Preliminary tests on the substance have shown it to be corn starch. Officials say that the letters were clearly intended to spread panic.

The most recent batch of letters were sent to Askew Elementary, Austin High School, Benbrook Elementary and the Bellfort Early Childhood Center.

One veteran postal inspector told Examiner.com that the envelopes will provide plenty of evidence, including fingerprints on the letters or DNA from hairs or spit from licking the envelopes.

Officials believe that the suspect may be using a published list of schools in the district as nearly all of the schools to receive the letters so far have started with the letters "A" and "B."