Czech Prime Minister Andrej Babiš’ son said he had been lured to Crimea and abducted to stop him testifying about alleged criminal fraud in his father’s business dealings.

As reported by the Guardian, the Czech news site Seznam Zprávy broadcast a documentary that included footage of his son, Andrej Babiš Jr, making dramatic allegations apparently implicating his father.

In response, opposition parties demanded a parliamentary no-confidence vote on Babiš’ minority coalition government.

Babiš, 35, tracked down to Switzerland, where he was living with his mother, the prime minister’s first wife, said he had been persuaded to go to Crimea at a time when police were seeking to question him. Babiš, who has a history of mental health problems, had been given the choice of “taking an extended holiday” or being admitted to a psychiatric hospital.

Once in Crimea he was forcibly detained by two Russians, one of whom was a psychiatrist who had previously treated him during a stay in a Prague mental hospital, he claimed.

Babiš has been charged, along with his father, in the long-running investigation into allegations that nearly €2m in EU funds was falsely obtained by one of the latter’s businesses, Čapí Hnízdo (Stork’s Nest), a hotel and conference centre south of Prague.

According to the Guardian, police have still to interrogate the prime minister’s son, having been unsure of his whereabouts after he left the Czech Republic, leaving the prosecution effectively stalled.

The Czech prime minister, the country’s second richest man, posted on Facebook he said his son was mentally ill and on medication and also that his daughter, Andrea, had bi-polar disorder. “No one kidnapped my son, he left the Czech Republic voluntarily,” he wrote, adding that police had investigated the alleged kidnapping and dismissed it.