The U.S. Secret Service confirmed Tuesday it was aware of several mailings to Chicago's DuSable Museum of African American History, which museum officials call "threatening."
The letters were addressed to Perri Irmer, the president and CEO of the museum, with the museum’s Washington Park address.
"Any threat that is channeled through us is a threat to us," said Irmer. "In today’s climate, we have to take everything seriously."
The handwritten letters, sent from Indiana, show images of the Obamas, Vice President Kamala Harris, President Joe Biden and other Democratic leaders.
Some of the pictures are surrounded by Bible verses and stickers that say "funeral."
The sender also pushed conspiracy theories about the presidential election.
Reopening to the public in June, DuSable Museum officials are looking into hiring armed guards, but funding is already sparse.
A spokesperson with the U.S. Secret Service said they were aware of the communications sent to the museum but wouldn’t confirm or deny specifics of the investigation. The spokesperson added the U.S. Secret Service investigates all threats made against those they protect.
"It’s the very messaging, the very education, the very information that we represent that is the subject of the target," said Irmer.
Rev. Jesse Jackson, Sr. also released a statement on Tuesday, calling on President Biden to intervene to "stop the cycle of violence and intimidation."
Museum officials told NBC 5 the investigation in the mailings is ongoing.