A 24-year-old Massachusetts man was arrested and charged on Thursday with sending a threatening message and suspicious white powder to President Donald Trump's eldest son last month, officials said.
The letter was opened at Donald Trump Jr's New York apartment on February 12. His wife Vanessa was taken to hospital as a precaution after opening the envelope.
Daniel Frisiello from Beverly, north of Boston, allegedly sent the letter and similar threats to four other prominent individuals across the country.
The five envelopes were postmarked Boston and each contained a threatening message and a white powdery substance. No one was hurt in any of the incidents and the substance was deemed not hazardous, federal officials said.
The message to the president's son called him an "awful, awful person" and threatened the 40-year-old father of five was "getting what you deserve," officials said.
Frisiello was charged with five counts of mailing a threat to injure and five counts of false information and hoaxes. Each charge carries a maximum prison term of five years.
He is due to appear before a federal court in Worcester, Massachusetts later on Thursday.
Trump Jr, an outspoken defender of his father, called the incident "truly disgusting."
He and his brother Eric Trump live in New York and run the family real-estate business, taking over after their father took office in January 2017.