MOSCOW — Russian police on Thursday released a well-known opposition politician from custody after holding him for two days.

Dmitry Gudkov was detained at his country house on Tuesday in connection with an investigation into money allegedly owed to the city for office space rental. Gudkov’s attorney, Mikhail Biryukov, said it was not clear whether his release meant the investigation was still active, according to Russian news reports.

His detention comes as authorities continue to crack down on dissidents ahead of September’s parliamentary election, in which Gudkov aspired to run. He was a parliament member from 2011 to 2016.

On Wednesday, a court sent prominent opposition figure Andrei Pivovarov to jail for two months pending a probe into his actions as head of the Open Russia group, which authorities have declared an undesirable organization. Pivovarov had announced the group was disbanding several days before his arrest.