Four men, including a police officer, have been remanded in custody by a Turkish court over the death of an anti-government protester who was beaten during a June demonstration, local media reported.

The four were placed in detention by a court in the northwestern city of Eskisehir on Wednesday where university student Ali Ismail Korkmaz, 19, died of a brain haemorrhage on July 10 after spending 38 days in a coma.

The prosecutor said investigators were seeking to identify another suspect, while three others have been released, the Dogan news agency reported.

Evidence against the men was captured by a security camera, which recorded video of four people beating the victim with sticks in a dark alley.

This is the first detention related to deaths that occurred during nationwide protests in June. A police officer who allegedly shot dead a protester in a rally in the capital, Ankara, was released by a court which said he acted in "self-defence."

The protests in Turkey began with a sit-in to save a park in Istanbul, which was supposed to be razed in a redevelopment project. Police cracked down on the protest on May 31, and the demonstration soon escalated into countrywide demonstrations against the Islamist-rooted government.

According to police, about 2.5m people took to the streets in 80 towns over three weeks to protest against Prime Minister Recep Tayyip Erdogan, who was accused of becoming increasingly authoritarian and trying to "Islamise" Turkish society.

The subsequent clashes left five people dead, including one policeman, and more than 8,000 people were injured, according to the Turkish doctors' union.

Erdogan has been in in power since 2002 and won three elections in a row, taking nearly half the vote in 2011 after presiding over years of strong economic growth.

Source: Agencies