Donald Trump Jr.’s wife and mother-in-law were hospitalized as a precaution on Monday morning after opening an envelope containing a white powdery substance that investigators later determined was cornstarch and was not hazardous, police officials said.
The letter, addressed to Donald Trump Jr., was sent to the Manhattan apartment of his mother-in-law, Bonnie Haydon, the officials said.
Ms. Haydon passed the letter to her daughter, Vanessa Trump, around 10 a.m. When she opened it, at least one of them appeared to start coughing and felt nauseous, one of the officials said.
They called 911, and the New York Police Department and Fire Department responded to the apartment, on East 54th Street in the Sutton Place neighborhood.
Medical personnel from the Fire Department, after initially being called to stand by in case they were needed, took Ms. Haydon, Ms. Trump and a third person to NewYork-Presbyterian/Weill Cornell Medical Center as a precaution. It was not clear who the third person was.
They were all expected to be fine, the police officials said, and the powder was determined not to pose a threat.
In the past, the Police Department has found that letters like the one on Monday have the potential to generate copycat threats, said J. Peter Donald, assistant commissioner in the department’s public information office.
The investigation into the letter on Monday was being led by the New York Joint Terrorism Task Force — not because investigators believed it was an act of terrorism, but because the task force tends to take the lead on white powder threats.
Members of the New York Police Department’s Intelligence Bureau and hazardous materials teams and the Secret Service were also involved in the early stages of the investigation.