WASHINGTON (Reuters) - Washington police and fire officials on Tuesday removed a powdery substance sent to the office building where former U.S. President Barack Obama leases space, but the material was found to be harmless, the U.S. Secret Service said.

A package “containing an unknown powdery substance” was discovered in the headquarters of the nonprofit World Wildlife Fund (WWF) in Washington, Secret Service spokesman Jeffrey Adams said in a statement.

The local Fox affiliate said it was not known if Obama was in the office he has in the building at the time of the incident. The package was mailed to the WFF, Fox reported.

“Preliminary investigation determined that the package was not addressed to any Secret Service protectees,” Adams said.

The substance was determined to be harmless, he said, and the Secret Service will investigate the incident further.

On Monday, U.S. President Donald Trump’s daughter-in-law, Vanessa Trump, was hospitalized in New York after coming in contact with a suspicious powder contained in a letter sent to a family’s home. That powder also proved harmless, according to police.

The package included a letter addressed to the president’s oldest son, Donald Trump Jr., that read “You’re an awful person and now you get what you deserve,” the New York Post and New York Daily News reported, citing unnamed law enforcement sources.

Obama and his wife Michelle, who took up residence in Washington after leaving the White House last year, took part in a ceremony on Monday at the Smithsonian’s National Portrait Gallery where their official portraits were unveiled.