Donald Trump’s “election protection” effort will be run by Mike Roman, a Republican operative best known for promoting a video of apparent voter intimidation by the New Black Panthers outside a polling place in 2008.

Roman is to oversee poll-watching efforts as Trump undertakes an unprecedented effort by a major party nominee by calling into question the legitimacy of the popular vote weeks before election day.

The Republican nominee has insisted, without evidence, that dead people and undocumented immigrants are voting in the United States.

Trump has long claimed that the 2016 election is rigged but has amplified his claims of voter fraud in recent days. On Monday he tweeted: “Of course there is large scale voter fraud happening on and before election day. Why do Republican leaders deny what is going on? So naive!” In particular Trump claimed in an interview with Fox News that voter fraud was rampant in cities including Philadelphia, St Louis and Chicago after long warning vaguely about fraud in “certain communities”.

Multiple sources have confirmed to the Guardian that Roman, who also previously ran the Koch network’s now defunct internal intelligence agency, will oversee the Trump campaign’s efforts to monitor polling places for any signs of voter fraud.

Roman is best known for his role in promoting a video that showed two members of the New Black Panthers – a fringe group that claims descent from the 1960s radicals – standing outside a Philadelphia polling place dressed in uniforms, with one carrying a nightstick. Police are called and the two men leave.

A justice department investigation into the incident – filed in the weeks before George W Bush left office – became a political football that divided career lawyers within the justice department. The incident was repeatedly cited as evidence of Democrats setting out to harm the election process.

The case was eventually dropped but not before it became a conservative cause célèbre. As Rick Hasen, a election law professor at the University of California, Irvine, said: “It was one of the most retold stories on Fox News and the right for years and took on almost mythical status as evidence of thuggery by Democrats to harm the voting process.”

Hasen, who viewed the case as a “complete tempest in teapot”, said of Roman that he was “somebody who has been more willing to put forth more outrageous statements about voter fraud and election process”. Hasen added: “I don’t consider him a very responsible voice among Republicans on this question and I’m not surprised that Trump would be using him for polling related efforts.”

The Trump campaign did not immediately respond to a request for comment.