Daniel Frisiello, a 24-year-old man from Beverly, Massachusetts, was arrested Thursday for allegedly sending a hoax letter containing white powder to Donald Trump Jr.'s home last month. Frisiello is expected to appear in federal court in today after a criminal complaint was filed by the Massachusetts U.S. Attorney's Office.

Flashback: Vanessa Trump was sent to the hospital on February 12 as a precaution after opening the letter. Law enforcement officials later said the powder was probably cornstarch.