The well-known 36-year-old investigative journalist Ivan Golunov was placed under two months' house arrest in Moscow on Saturday while he is investigated for drug peddling.
The journalist was on his way to a meeting with a source on Thursday when he was searched and arrested in Moscow on drug charges, according to a statement by his employer, Meduza.
The authorities said they found illegal substances, first in a rucksack being carried by Golunov and later in his Moscow apartment.
But a lawyer for Golunov claimed the drugs were planted and said his client was beaten while in custody.
Golunov is well known for his investigative reports for the Meduza news website into corruption among Moscow officials.
"We have reason to believe he’s been targeted because of his work as a journalist," Meduza said in a statement.
"Pretty much every investigation done by Ivan Golunov hurts someone's interests,” colleague Illya Zhegulev said. “In most cases, it’s the interests of officials covering up illegal businesses, or those of security forces representatives. He is one of the best investigative journalists in the country."
Supporters protesting against the arrest were also detained.
The British Embassy in Russia tweeted that the reports were "concerning" and the US Embassy tweeted in Russian that they "call for the release of Ivan Golunov" stating he should not be "persecuted for his professional activities".
Drugs convictions can carry sentences of up to 20 years in prison.
This story has been updated as events unfold.