(CN) - The New York City Police Department, Secret Service and FBI are investigating a threatening letter sent to the Manhattan apartment of Donald Trump's son Eric.
Officials say the envelope sent to Eric Trump's apartment on Central Park South on Thursday contained a suspicious white powder.
CBS Newsradio 880 in New York is reporting it also contained a note warning the Donald Trump, the frontrunner for the Republican presidential nomination, to drop out of the race, or a family member would get hurt.
Trump's daughter-in-law Lara reportedly opened the envelope, but neither she nor anyone else was hurt.
Officials say preliminary tests indicated the white substance was not hazardous.
Previously Donald Trump had been the subject of an unrelated death threat from a 23-year-old Egyptian living in the U.S. who said on Facebook that he'd gladly spend the rest of his life in prison for killing the presidential aspirant.
"The whole world would thank me for doing that," said El-Din Ali Mohamed Nasr El Sayed in the post.
Earlier this month, a California immigration court announced it will deport El Sayed over the threat.
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