By Marcy Norton

PHILADELPHIA (CBS) — A source confirms that someone sent a threatening letter to Donald Trump’s sister in Philadelphia, demanding that the billionaire drop out of the presidential race.

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Judge Maryanne Trump Barry serves on the U-S Court of Appeals for the Third Circuit, which includes southeastern Pennsylvania, and sits in Philadelphia.

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The judge, who is 78 years old, is Donald Trump’s older sister, and she has been largely quiet during the raucous campaign.

Last week, Donald Trump’s son Eric received a similar letter, which also contained a white powder that was later determined to be harmless. The letter sent to Judge Barry did not contain any powdery substances.

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The Philadelphia FBI office issued a statement saying the agency is aware of the incident and is working closely with the Secret Service and the US Marshall’s Service, but couldn’t comment further