Turkish police on Monday detained at least 47 academics and university staff, saying that it was part of an investigation into the Gulen movement blamed for last year's failed coup attempt.

In total, 72 arrest warrants were issued targeting academics and staff at the elite English language Bogazici University and Medeniyet University in Istanbul.

Among those detained was Koray Caliskan, a liberal government critic and former adviser to the main opposition People's Republican Party (CHP) leader Kemal Kilicdaroglu.

Caliskan's writings and commentary suggests he has no affiliation with Islamic parties.

Read: Turkey's 'March for Justice': opposition calls for unity and reform

Both active academics and several who had already been dismissed were detained on suspicion of using the encrypted messaging app ByLock, Turkish media reported. Thousands of people have been arrested for allegedly having the messaging app, which authorities say the followers of US-based Islamic cleric Fethullah Gulen used to communicate and plan the coup attempt.

Gulen, a former ally of President Recep Tayyip Erdogan, denies any involvement in the failed coup.

Watch video 28:31 Share Turkey one year after the failed coup Send Facebook google+ Whatsapp Tumblr linkedin stumble Digg reddit Newsvine Permalink https://p.dw.com/p/2gF8C Turkey One Year after the Failed Coup

More than 50,000 people including soldiers, civil servants, teachers and academics have been arrested in a massive crackdown since last July's failed coup attempt. Some 150,000 others have been dismissed from their jobs under sweeping emergency powers granted to the government in the wake of the coup attempt. Hundreds of media outlets, NGOs and rights groups have also been shuttered.

The latest arrests come a day after Kilicdaroglu ended a nearly 450-kilometer (280-mile) "March for Justice" from Ankara to Istanbul by holding a rally attended by more than a million people calling for an end to emergency rule and injustice.

Kilicdaroglu told the crowd Erdogan had used the July coup attempt to carry out a "palace coup" against democracy and justice. He demands an end to emergency rule, independence of the judiciary, the release parliamentarians from prison and the scrapping of what he considers to be tainted 2017 referendum results that granted Erdogan sweeping presidential powers.