WASHINGTON (AP) — Homeland Security Secretary Kristi Noem said Thursday that federal law enforcement is investigating a social media post made by former FBI Director James Comey that she and other Republicans suggest is a call for violence against President Donald Trump.

In an Instagram post, Comey wrote “cool shell formation on my beach walk” under a picture of seashells that appeared to form the shapes for “86 47.”

Numerous Trump administration officials, including Noem, said Comey was advocating for the assassination of Trump, the 47th president. “DHS and Secret Service is investigating this threat and will respond appropriately,” Noem wrote.

Merriam-Webster, the dictionary used by The Associated Press, says 86 is slang meaning “to throw out,” “to get rid of” or “to refuse service to.” It notes: “Among the most recent senses adopted is a logical extension of the previous ones, with the meaning of ‘to kill.’ We do not enter this sense, due to its relative recency and sparseness of use.”

The post has since been deleted. Comey subsequently wrote, “I posted earlier a picture of some shells I saw today on a beach walk, which I assumed were a political message. I didn’t realize some folks associate those numbers with violence.

“It never occurred to me,” Comey added, “but I oppose violence of any kind so I took the post down.”

Comey’s original post sparked outrage among conservatives on social media, with Donald Trump Jr. accusing Comey of calling for his father’s killing.

Current FBI Director Kash Patel said he was aware of the post and was conferring with the Secret Service and its director.

James Blair, White House deputy chief of staff for legislative, political and public affairs, noted that the post came at a delicate time given that Trump is traveling in the Middle East.

“This is a Clarion Call from Jim Comey to terrorists & hostile regimes to kill the President of the United States as he travels in the Middle East,” Blair wrote on X.

Comey, who was FBI director from 2013 to 2017, was fired by Trump during the president’s first term amid the bureau’s probe into allegations of ties between Russian officials and Trump’s 2016 presidential campaign. Comey wrote about his career in the best-selling memoir “A Higher Loyalty.”

He is now a crime fiction writer and is promoting his latest book, “FDR Drive,” which is being released on Tuesday.