A one-time business partner of the former national security adviser Michael Flynn has been arrested and charged with illegally lobbying to have a Turkish exile returned from the US.

Bijan Rafiekian, who also goes by the name Bijan Kian, made an initial appearance on Monday in federal court in Alexandria, Virginia.

He was indicted on charges including failing to register as a foreign agent.

According to the indictment unsealed in court, Rafiekian was vice-chairman of Flynn’s business group, the Flynn Intel Group. The two worked throughout 2016 to seek ways to have the cleric Fethullah Gülen extradited from the US to Turkey.

The Turkish president, Recep Tayyip Erdoğan, has accused Gülen of directing a failed coup in the country.

Flynn is referred to in the indictment as “Person A”.

Ekim Alptekin, a Turkish businessman regarded as close to Erdoğan, was also charged in the indictment, the filing shows.

Meanwhile Flynn is to be sentenced on Tuesday after pleading guilty to lying to the FBI over his contacts with Russian officials after Donald Trump was elected president in November 2016.

The indictment accuses Rafiekian and Alptekin of illegally lobbying in the US to discredit Gülen and have him extradited. According to the indictment, Alptekin worked at the direction of the Turkish government, but the defendants worked to conceal that fact.

In the summer of 2016, when Flynn was working as an adviser to the Trump campaign, the three initiated what they called a “truth campaign” that compared Gülen to Iran’s Ayatollah Khomeini.

On 8 November 2016, election day, Flynn wrote an op-ed piece in the Hill newspaper titled “Our Ally Turkey Is in Crisis and Needs Our Support”. The column uses the same comparison between Gülen and Khomeini. The indictment noted Flynn’s column uses identical or very similar language to that prepared by Rafiekian in a draft op-ed.

“We all remember another quiet, bearded elder cleric who sat under an apple tree … in the suburbs of Paris in 1978,” Flynn wrote in the op-ed, mimicking language provided to him by Rafiekian. “He claimed to be a man of God who wanted to be a dictator.”

Several days before the column was published, Rafiekian crowed to Alptekin in an email about the advantageous timing of the pending op-ed piece coinciding with election day. “The arrow has left the bow!”

Alptekin, who had complained a week earlier that the Flynn Intel Group had not done enough work to honor the contract, responded that Rafiekian’s op-ed was “right on target”.

Rafiekian and Alptekin’s prosecution is led not by the special counsel but prosecutors with the eastern district of Virginia.