CNN  — 

On Wednesday night, federal agents seized a cell phone belonging to Richard Burr, according to the Los Angeles Times, as part of a broader investigation into stock sales made by the North Carolina Republican senator in the lead-up to the nationwide closures due to the coronavirus.

Which is a very big deal – for several reasons.

First and foremost, it suggests a seriousness in terms of the investigation that we were not aware of prior to Wednesday. That investigators were able to obtain a warrant – and seize Burr’s cell phone – suggest they have reason to believe that Burr’s actions merit a much closer look. It also suggests, as CNN security correspondent Josh Campbell, a former FBI official, has noted that the top officials at the Department of Justice are aware of the investigation because when the FBI looks into an elected official it falls under the category of a “Sensitive Investigative Matter.” Additionally, Campbell pointed out, since FBI agents work with prosecutors to obtain search warrants, the Justice Department would have been aware of any court orders requested by the FBI to search Burr’s phone for possible evidence of criminal activity.

In short: Federal officials don’t get or execute a warrant against a sitting US senator on a whim. Or without the top officials at Justice knowing about it.

At issue for Burr is his sale of up to $1.7 million in stocks in February before the economy began to crater as a result of shutdowns caused by the coronavirus but after he – and other senators – took part on private briefings about the possibly catastrophic impacts coronavirus could have on the country. (Several other senators also made a series of stock trades during that time, including Georgia Sen. Kelly Loeffler.)

Burr has repeatedly denied any wrongdoing. His office did not respond to CNN’s request for comment about the LA Times reporting.

But those denials are likely to come into further question given the seizure of Burr’s phone. And the events of Wednesday night have already had an impact: Burr is stepping down as chair of the Senate Intelligence Committee.

“Senator Burr contacted me this morning to inform me of his decision to step aside as Chairman of the Intelligence Committee during the pendency of the investigation,’ Senate Majority Leader Mitch McConnell said in a statement Thursday afternoon. “We agreed that this decision would be in the best interests of the committee and will be effective at the end of the day tomorrow.”

In so doing, Burr follows in the footsteps of New Jersey Sen. Bob Menendez, who was indicted in 2015 on corruption charges. Menendez stepped down as the top Democrat on the Senate Foreign Relations Committee following the indictment although he maintained his innocence throughout. In 2017, the Menendez trial ended in a hung jury. Months later, in early 2018, the Justice Department dropped the charges against the New Jersey senator. (Menendez won a third term in 2018 against a heavy-spending Republican opponent.)

Burr’s decision to step aside as chair comes shortly after the conclusion of the committee’s high-profile investigation into Russia’s attempted interference in the 2016 election. The committee concluded that Russia had sought to interfere in the 2016 election to aid Donald Trump and hurt Hillary Clinton. Trump has repeatedly called the entire issue of Russian interference a “hoax.”

The events of Wednesday night and Thursday morning will also raise questions about Burr’s political future.

He was reelected to a third Senate term in 2016 with 51% of the vote; he is up for a fourth term in 2022 in what is likely to be a major target – even more so now – for Democrats. Should Burr resign (and in 2016, he said it was his last run for elected office) it would not, really, be entirely up to Democratic Gov. Roy Cooper to appoint his replacement. Under a state law passed in 2018, the Republican state committee would propose three possible picks to Cooper and he would be required to pick one.

And, the special election race to fill Burr’s term would also be a bit complicated. “If, hypothetically, Burr were to step down, there would be a special election for his seat ONLY if his resignation was effective more than 60 days before Election Day, that is, before September 4, 2020,” tweeted Inside Elections Jacob Rubashkin. “If it’s on or after that date, the special wouldn’t be till 2022.”

Obviously we have more questions than answers at the moment when it comes to the investigation into Burr and what it might mean for his political future. But none of the questions – or potential answers – look good for Burr right now.