The man, Bernhard Laufer, was to appear later today in federal court in Brooklyn.
According to a criminal complaint, Laufer began sending the emails last year to the Washington-based Council on American-Islamic Relations. The group identified the recipient as its national executive director, Nihad Awad.
Laufer, 56, was already facing attempted murder charges alleging he stabbed a man at a mosque in 2012 while yelling, "I will kill you Muslim." He was out on USD 200,000 bail when he sent an email accusing the Muslim group of framing him, warning, "CAIR will now be destroyed," court papers say.
In a statement, CAIR called the case "another incident demonstrating the actual, imminent harm that can result from Islamophobia."
The name of Laufer's attorney wasn't immediately available.