Police in Moscow released prominent Russian opposition politician Dmitry Gudkov from custody on Thursday, but have kept him as a suspect in a criminal case that prompted his arrest two days ago, his lawyers said. The 41-year-old former member of parliament was detained on Tuesday amid a crackdown on the Kremlin"s political opponents that comes ahead of parliamentary elections in September. He was suspected of failing to pay a debt on a rented property dating from 2015-17, according to state media. His father, Gennady Gudkov, has said that property was in no way linked to his son. Law enforcement have not detailed the case publicly. Gudkov could face up to five years in jail if charged and found guilty, the state TASS news agency has reported. A court was expected to consider the terms of his pre-trial custody on Thursday, but the hearing did not take place and he was instead released as 48 hours had elapsed since his arrest. It was unclear why the hearing did not take place. His aunt, Irina Ermilova, who was also a suspect in the case, was released after appearing at her hearing, a court said. Russia"s beleagured opposition has accused authorities of trying to smother its activities ahead of elections for the lower house of parliament in September. A court is expected to meet next week to consider banning jailed Kremlin critic Alexei Navalny"s movement as "extremist". Last Monday, an opposition activist, Andrei Pivovarov, was taken off a flight bound for Poland and jailed for two months pending trial for allegedly breaking Russia"s law against "undesirable" organisations. Dmitry Gudkov"s father, Gennady, who is also a Kremlin critic but lives abroad, said on Thursday that authorities had opened a criminal case against him over ammunition found during a search of his property this week. He said the ammunition was an award he received in 2005 and that the police had been earlier informed about it. He accused authorities of trying to stop him from being able to return to Russia. There was no confirmation of the case from law enforcement.