Federal authorities are investigating large markings of the numbers “8647” that appeared in the grass of the National Mall in Washington, D.C. On Thursday morning. U.S. Park Police responded to a report of vandalism on the west lawn of the Washington Monument at approximately 11:30 a.m. ET. While the markings are located near the World War II Memorial, the cause of the discoloration has not yet been determined, and police have collected grass samples for testing. The markings have prompted a response from the White House and the Interior Department. An Interior Department spokesperson described the incident as “deranged” vandalism that “will not be tolerated,” stating that any threat against the President is taken seriously. White House spokesperson Davis Ingle issued a statement condemning anyone who endorses “political violence or assassination culture,” suggesting they seek psychiatric help for “Trump Derangement Syndrome.” Trump administration officials claim the numbers are meant to encourage violence against Trump, who is the 47th president. The sequence of numbers is linked to a criminal case against former FBI Director James Comey, who was indicted in April. The Justice Department argued that Comey threatened President Trump’s life by posting a photo of seashells arranged to display “8647” on Instagram. Comey has denied the charges, calling the prosecution politically motivated, and stated he did not realize some people associate the numbers with violence. While the term “86” is common restaurant lingo for an item that has run out, Trump has stated the term connotes violence and, when paired with “47,” means “kill President Trump.” The incident occurs as the National Mall prepares for several events honoring the U.S. 250th anniversary this summer. In a separate case this month, a federal judge ruled that “8647” by itself is not a threat, stating that a protest flag with those numbers flying on land managed by the National Park Service constituted free speech.