At least 100 people gathered in central Moscow Friday evening to hold single pickets against the arrest of investigative journalist Ivan Golunov.

Golunov, an investigative reporter for the Meduza news website, was detained Thursday afternoon on drug trafficking charges which his colleagues say were “persecution” for his reports. Russia’s independent trade union of journalists on Friday called for members to hold single pickets in support of Golunov outside police headquarters in their cities.