DALLAS - There were four cases of mysterious, white powder found in envelopes Monday at North Texas schools and a large Dallas business also was the recipient of such a letter.
Police in all of the cities where the powder was found say it is harmless. Dallas police said in their case, the powder was corn starch.
Powder was found at Gulledge Elementary in Plano, Don Whitt Elementary and Wylie High School in Wylie ISD, and Sunset High School in Dallas.
Around 10:30 a.m. a teacher at Sunset High found a threatening letter containing the white powder. Emergency personnel quickly responded and found that the powder was harmless corn starch. The school was put on lockdown while the incident was investigated.
Another envelope containing white powder was found at Gulledge Elementary. Plano police and fire officials said the powder in that case was also harmless.
Don Whitt Elementary in Sachse and Wylie High School, both part of Wylie ISD, also reported envelopes with white powder arriving at their respective campuses Monday. In those cases, the powder was again found to be harmless, and classes were not interrupted.
Texas Instruments said they, too, received a letter containing white powder Monday, but like the others it was deemed a non-threat.
The FBI is now involved in the investigation, since multiple cities are involved. The letters were similiar to letters sent from Dallas and received in Washington D.C. at multiple schools in May 2011.