IN A region where the rule of law is shaky, the International Commission against Impunity in Guatemala (CICIG) has become something of a beacon. Set up in 2006 to aid the country’s weak prosecutors, the UN-backed body has aided investigations that led to the removal and jailing of a president, and the dismantling of death squads and drug-trafficking rings. These successes have earned it enemies—including the current president, Jimmy Morales, who tried to get its head fired last year after it accused him of accepting illegal campaign funding. On April 20th, following a public apology by a group of businessmen who made the contributions, the president demanded that CICIG’s founding agreement be investigated. Guatemala’s “net centres”, groups of online trolls paid to smear opponents of the powerful, have raised their output.

With one in five members of congress under investigation, Mr Morales is not the only powerful Guatemalan who would like to see CICIG go. Yet every time its mandate has come up for renewal, the government has approved an extension, partly because the United States, which provides half of CICIG’s budget, has advocated its preservation. Now, however, Guatemala has become a pawn in a longstanding battle over corruption on the other side of the world. CICIG’s new adversary is Bill Browder, an American-born financier who made his fortune in Russia before falling out with the Kremlin and mounting a global lobbying campaign against Vladimir Putin, Russia’s president.

Mr Browder pushed hard to win passage in America of the Magnitsky Act, which originally targeted Russian officials responsible for the death of his tax accountant in a Russian jail. It later morphed into a broader law against human-rights abuses. Mr Browder heard of the case of a Russian family who had sought refuge in Guatemala but ended up jailed there instead. He has accused CICIG of taking money from the Russian government, and persuaded America’s Congress to hear his concerns. On April 27th a bicameral commission will hold a session entitled “The Long Arm of Injustice: Did a UN commission founded to fight corruption help the Kremlin destroy a Russian family?”

The family in question is that of Igor and Irina Bitkov, who once owned a timber plant in the north-west of Russia. Their firm was forced into bankruptcy by state banks, and in 2009 they fled to Guatemala, fearing for their safety. Their teenage daughter Anastasia later joined them. In 2015 all three were arrested as part of a CICIG investigation into a passport-forgery network. Earlier this year, they were given harsh sentences for using fake documents and identities. Igor received 19 years in prison, Irina and Anastasia 14.

The Bitkovs say they are innocent victims. They claim they were defrauded of their business in Russia in a way similar to that experienced by Mr Browder. They decided to flee and saw an ad for a law firm offering Guatemalan passports for an “assessment fee” of $50,000 per person. They paid the money, flew to Guatemala and picked up their passports at the migration agency. They say they were shocked to find themselves in handcuffs six years later, unaware that they had committed any crime.

CICIG insists that the Bitkovs were treated the same as every other suspect in the fake-passport case. It started in 2010 and yielded 39 convictions. A raid on the migration agency in 2014 turned up the Bitkovs’ names, and a search of their house revealed stashes of cash and that Igor had documents corresponding to three separate identities. Prosecutors pursued maximum sentences for everyone involved. Other suspects received reduced jail time for providing information, but the Bitkovs declined a deal. The family has been represented by inexperienced lawyers, who seem to have served them poorly. The couple did not submit evidence to show that they had been persecuted in Russia, or prove that they bought their passports from a private company.

The Bitkovs suspect something more sinister. Over a year before their arrest, VTB—a state-owned Russian bank, which was the largest creditor of the Bitkovs’ firm—filed a legal claim in Guatemala, accusing them of committing fraud and laundering money to avoid repaying their loans. At the Bitkovs’ first court date, they say they were astonished to see VTB’s representatives in the courtroom. The couple concluded that their tormentors had followed them to Central America. They soon got in touch with Mr Browder, who believes that VTB’s involvement shows that CICIG, a body intended to fight the corruption of state institutions, has itself been infiltrated by Russia.

No evidence has emerged demonstrating Russian meddling. Although the claims brought by VTB and state prosecutors were merged at the outset—a standard procedure—a judge later dismissed VTB’s filing, ending its involvement. Moreover, CICIG does not control the case: it is the Guatemalan courts that sentenced the Bitkovs and will hear their appeals. The only witnesses on the schedule for the congressional hearing are the Bitkovs’ lawyers and Mr Browder, who says he will demand that American funding for CICIG be suspended until the Bitkovs are released.

Mr Browder admits that he is unfamiliar with the Guatemalan justice system, and that “anti-CICIG people...have been looking for a case like this.” CICIG and its defenders hope that his crusade to save the Bitkovs from dark elements of one corrupt country does not enable those in another to exploit his efforts.