On Feb. 12, an envelope addressed to Prince Harry and Meghan Markle was found to have both a threatening letter and a white powdery substance inside.

According to TIME, the letter reportedly stated that the powder was anthrax, which caused a full security scare, however it was tested and found to be harmless.

“Police are investigating after a package containing a substance was delivered to St James’ Palace on Monday, 12 February,” the Metropolitan Police shared in a statement. “The substance was tested and confirmed as non suspicious. Officers are also investigating an allegation of malicious communications which relates to the same package.”

TIME additionally noted that St. James’ Palace is home to Prince Charles and his wife, Camilla, along with Princess Anne and Princess Alexandra, the Queen’s cousin.

Luckily for the entire royal family the powder was a hoax, but moreover they’d likely never come in contact with it anyway. As HuffPost noted, protocol means that staffers open all mail addressed to the members of the royal family first.

However, if the powder had been actual anthrax the staff would have been in grave danger. According to the Centers for Disease Control and Prevention, anthrax is a “serious infectious disease” and can cause “severe illness in both humans and animals” who come into contact with it.

The royal couple weren’t the only ones to receive the threatening piece of mail either. According to the Evening Standard, another letter containing white powder was also sent to the office of Home Secretary Amber Rudd. That powder was found to be harmless as well.

As public figures, security threats unfortunately tend to come with the territory. However, this letter likely means security will be heightened even further during Meghan and Harry’s wedding this coming May.

In fact, the Evening Standard reported, security measures for the big wedding day are already under review. Authorities are preparing for anything from a terror attack to individual stalkers.

And though Meghan isn’t quite an official royal yet, she has already been assigned a 24/7 guard from the Royalty and Specialist Protection command, meaning she can sleep easy tonight knowing the best of the best are protecting her from harm.