A US federal agency has opened a formal investigation into former Special Counsel Jack Smith, who oversaw two criminal probes into President Donald Trump following his first term in the White House.
The Office of Special Counsel (OSC) confirmed that it was investigating whether Mr Smith violated the Hatch Act, a law prohibiting federal employees from using their position for political activity.
The decision follows a request for a probe by the US Senator Tom Cotton, an Arkansas Republican.
The OSC is an independent agency that investigates the conduct of federal employees, but it does not have the authority to bring criminal charges.
It is different from the type of special counsel's office previously overseen by Mr Smith, who was appointed by the Department of Justice to pursue criminal cases.
The OSC's investigation, which was first reported by the New York Post, is the latest in a series of actions taken by Mr Trump and his allies against their perceived political enemies.
Mr Smith, who resigned from his post in January following Mr Trump's election victory, could not immediately be reached for comment.
Earlier this week, Mr Cotton accused Mr Smith of aggressively pursuing his cases against Mr Trump with the aim of hurting his presidential campaign.
He called Mr Smith "a political actor masquerading as a public official" in a series of posts on X.
"That's why I've asked this unprecedented interference in the 2024 election be immediately investigated by OSC," Mr Cotton wrote on X.
A former war crimes prosecutor, Mr Smith brought two criminal cases against the US president: one accusing him of illegally retaining classified material and another related to Mr Trump's attempts to overturn his 2020 election loss, an effort that sparked the 6 January 2021, assault on the US Capitol.
Neither case went to trial, having been delayed and buffeted by a series of legal challenges, including a ruling by the Supreme Court's conservative majority that granted former presidents broad immunity from criminal prosecution.
Mr Smith dropped both cases after Mr Trump won the US presidential election, citing a longstanding Justice Department policy against prosecuting a sitting president.
But he issued a report in January saying evidence he gathered would have been enough to convict Mr Trump at trial.
Mr Trump denied wrongdoing and assailed the prosecutions as politically motivated attempts to damage his campaign.
