Days before the violent riot at the U.S. Capitol, a 45-year-old man in south suburban Chicago Heights threatened violence at President-elect Joe Biden’s inauguration in Washington, federal authorities here alleged Tuesday.

Prosecutors in Chicago said Louis Capriotti left a threatening voicemail message on Dec. 29 for an unnamed congressman from New Jersey. In the message, Capriotti allegedly said, “We will surround the motherf-----g White House and we will kill any motherf-----g Democrat that steps on the motherf-----g lawn.”

Capriotti also allegedly “related that if certain individuals ‘think that Joe Biden is going to put his hand on the Bible and walk into that f-----g White House on Jan. 20, they’re sadly f-----g mistaken,” according to court records.

Capriotti will remain in custody until a detention hearing Friday. At his court hearing Tuesday afternoon, U.S. Magistrate Judge Gabriel Fuentes noted that Capriotti is accused of making “multiple threats to multiple people,” including Biden, Vice President-elect Kamala Harris and members of Congress.

“Our office takes the security of our public servants very seriously,” said John Lausch, the top federal prosecutor in Chicago, whose office filed the case against Capriotti. “Individuals who cross the line of free speech by making unlawful threats will be held accountable.”

Authorities said Capriotti “has a history of leaving profane voicemails for members of Congress.” He was charged with transmitting a threat in interstate commerce. He had been scheduled to appear before a judge in Chicago at 3:30 p.m. Tuesday.

The alleged threats from Capriotti came a few days before before Wednesday’s deadly insurrection at the U.S. Capitol. The riot, which left five dead and temporarily suspended Congress, followed a rally where outgoing President Donald Trump called on supporters to march to the Capitol and “fight” to overturn his re-election defeat to Biden in November.

Federal and local prosecutors in Washington have filed charges against dozens of people who allegedly participated in the pro-Trump mob, including a businessman from northwest suburban Inverness.

Following last week’s mob violence at the Capitol, the FBI issued a bulletin warning of “armed protests at all 50 state capitols” in the days leading up to Biden’s Jan. 20th inauguration as president.

In a statement, an Illinois State Police representative said they’re aware of the threats and are “tracking possible events” in Springfield this weekend, where lawmakers may be in session.

“The ISP remain vigilant in our mission to protect the safety of those engaged in the process of democracy, constitutional rights and public institutions,” the statement reads. “The ISP and local law enforcement will have all available resources at our disposal to respond to threats identified through federal, state and local intelligence.”

Court records show Capriotti has been known for years to U.S. Capitol Police and the FBI, whose agents interviewed him twice and even warned him with potential arrest nearly a year before he was finally charged.

Cook County court records show Capriotti was convicted of making a harassing phone call in 2016, and was sentenced to probation for two years. He also has been arrested and charged repeatedly for offenses including domestic battery and violating an order of protection, records show.

In the newly filed complaint, authorities say they believe Capriotti has been leaving “disturbing, anonymous” messages with several members of Congress since 2017. In the messages, officials say, he often screamed, swore, referred to the coronavirus pandemic and made “derogatory remarks concerning the race, religion, political affiliation or physical appearance of certain members and others.”

The FBI met with him in 2017 and again last February in Orland Park, records show. Authorities say Capriotti admitted to making the calls to Congress and that they “could be interpreted as hateful and threatening.”

But the feds say Capriotti told the FBI he was “just f-----g with” the federal elected officials who got the messages and he “didn’t mean any ill will.”

“Agents advised Capriotti that he needed to stop making the calls in that manner and that if he continued to do so he may face charges,” according to court records.

Nevertheless, Capriotti made several more calls to Congress after Trump lost the November election, allegedly making false claims that he was an active-duty Marine who had killed terrorists, telling one elected official to “choke in hell,” and promising vaguely that “some big news is about to go down.”

In the Dec. 29 call to a congressman from New Jersey, prosecutors say Capriotti made reference to a former governor from New Jersey, who was not identified in court documents. Capriotti allegedly said he would “like to put one right in [the former New Jersey governor’s] f-----g dome.”

One former Republican governor of New Jersey, Chris Christie, was a longtime Trump ally but he called on the president to concede the election more than a month before Capriotti left that voicemail message.

In the message, the feds say, Capriotti also said, “Democrats are f-----g terrorists.”

Dan Mihalopoulos is an investigative reporter on WBEZ’s Government & Politics Team.