CHICAGO (CBS) — Trump Tower in Chicago received a letter that threatened to kill President Trump, police said Tuesday. The Secret Service says it has taken charge of the investigation.

The envelope contained an unknown white power and was sent to the Trump building at 401. N. Wabash.

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The Chicago Fire Department also was on the scene investigating.

Trump has visited his namesake hotel and tower several times, but has never lived here.

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His son, Donald Trump Jr., was there last summer, to address long-term vacancies in the lower level of building.

The president has been highly critical of Chicago’s ongoing gang gun violence, although recently violent crime has declined in the city.

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