A Russian journalist who carried out high-profile investigations into corruption has been arrested in Moscow. Ivan Golunov, a 36-year-old reporter for the Latvia-based news site Meduza, was detained by police on Thursday and accused of large-scale drug dealing.

He is due to appear in court in south-west Moscow on Saturday morning. Meduza’s editor and director said in a joint statement that Mr Golunov is “being persecuted because of his journalistic activities”. Mr Golunov has repeatedly exposed corruption among Moscow’s high-profile businesspeople and its political elite, as well as fraudulent financial schemes in the city.

“We will find out by whose will Vanya [Mr Golunov] is being pursued, and we will make this information public,” director Galina Timchenko and editor Ivan Kolpakov said. “We will protect our journalist by all available means.”

They added that he had received threats over the last few months, in connection with an as-yet-unpublished story he has been working on. His arrest sparked protests in Moscow and St Petersburg, and more than a dozen people – mostly fellow journalists – were reportedly detained and later released.

In recent years, many opposition figures and human rights activists have been detained on apparently fabricated drugs charges, which are widely seen as an attempt to quash political dissent. Journalists in Russia have often been harassed or attacked in recent years for their work. Much of Russia’s media is controlled by the state and Russia is ranked 83rd out of 100 countries for press freedom by Freedom House.

How was Ivan Golunov arrested?

Mr Golunov was on his way to meet another journalist on Thursday when he was stopped and searched by officers. They claim they found the synthetic drug mephedrone in his rucksack, and that a later search of his flat turned up more drugs and some scales – indicating that he was involved in dealing.

According to Meduza, he was beaten up by officers both during his arrest and later at the police station. He was only able to contact a friend after 14 hours, the statement added.

Russian journalist Olga Ivshina reports that the police published photos they claimed showed this drug paraphernalia in Mr Golunov’s flat, but these were later withdrawn.

The police, she adds, admitted that “most of the published photos had not been taken at Mr Golunov’s flat after all, but were related to another criminal investigation that might be linked to his detention”.

Mr Golunov’s lawyer, Dmitry Julay, told reporters that he had been denied food and sleep for more than 24 hours.