Letter threatening shooting found at UT Southwestern Medical Center

A letter threatening an active shooting was found this morning at the University of Texas Southwestern Medical Center in Dallas, the medical school said on Twitter.

One building on campus was evacuated as a precaution, the school said.

University Police are investigating and patrolling the campus, UT Southwestern said, adding that no immediate threats were discovered.

Additional details were not immediately available.

This story is developing. Please check back for more updates.