DESOTO (CBSDFW.COM) – Another letter containing suspicious white powder showed up in North Texas today.

This one was sent to a doctor’s office in DeSoto.

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The envelope was turned over to Dallas Fire-Rescue’s hazmat team, which determined it to be cornstarch.

The US Postal Service is also investigating.

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Last week, at least eight letters containing white powder were found in four different states, including at several North Texas schools.

In each case, the powder was found to be either cornstarch or another benign material.

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