A suspicious envelope was found at an east Houston school.
Houston Independent School District officials said the envelope was sent to Franklin Elementary, 7171 Canal, and found on Friday. The envelope was not opened, officials said.
The FBI, Houston Fire Department and HISD police were investigating the incident. The mailroom was quarantined.
Classes continued as normal.
This is the third envelope suspicious envelope to be sent to the school this year, but the first two contained a powdery substance. One was found on March 6 and another one was found on Dec. 21. Both were determined to contain a harmless substance.
Investigators have not said if they believe the same person mailed all of the envelopes. According to HISD, a letter will be sent home to parents explaining Friday's events.