For the past six years, someone has been mailing letters containing white powder from North Texas to cities across the United States and U.S. Embassies around the world. The man behind the mailings has been arrested and identified as 66-year-old Hong Minh Truong, according to federal authorities.
The FBI says it suspects the mailings of the envelopes over the last four years are the work of someone in Texas.
The envelopes were found at a high school and an elementary school.
A lockdown has been lifted after a Dallas high school got a scary piece of mail.