Denouncing the “lynching and murder” of Greek queer activist Zak Kostopoulos, human rights NGO Amnesty International called on Monday for a transparent probe to be conducted into the circumstances of the incident and the role of police.

“Zak was a human rights and an LGBQT activist, a homosexual, a drag queen and seropositive. He was beaten to death after he entered a jewellery store… after he was violently trapped,” reads Amnesty’s statement.

The 33-year-old died on Friday 21 September following an alleged theft attempt and after being assaulted repeatedly by an Athens jewellery shop owner, 73, and a passer-by, 55, while trying to get out of the store crawling through a shattered display window.

The two men, whose actions were recorded on a video taken from a building across the street, face charges of inflicting “fatal body injuries” but claimed they acted in self-defence.

A recently released coroner’s report found no conclusive evidence that Kostopoulos’ death was directly caused by the beating but the precise cause of death still remains to be identified.

Meanwhile, the stance of the police during the fatal attack has also been questioned, with accusations made that authorities failed to protect Kostopoulos and even exerted unnecessary violence by continuing to beat the suspect while injured.

This is not the first time that Greek police conduct has been subject to scrutiny during attacks against minority and vulnerable groups.

A report by Amnesty International, authored in 2014, looking into the “culture of abuse and impunity” in the Greek police force, highlighted among others ill-treatment of migrants, failure of the police to investigate hate crime, concerns against transgender people and failure to bring perpetrators to justice.