Turkish police detained the brother of convicted gang leader Sedat Peker on Sunday after Peker said he sent him on a failed mission to kill a Turkish Cypriot journalist 25 years ago on the orders of a former Turkish minister. Organised crime police detained Atilla Peker and a personal guard at a rented house in the Aegean province of Mugla, broadcaster NTV said.

The reported detention came hours after Sedat Peker, who has released a series of videos filled with accusations against officials and watched by millions of people, said he tasked his brother to kill politician and journalist Kutlu Adali in 1996.

Peker’s uncorroborated allegations against politicians stretching back decades have gripped viewers in Turkey, and threatened to tarnish the image of a government already struggling with economic woes and the COVID-19 outbreak.

President Tayyip Erdogan said in response to the videos last week that his government brought peace to Turkey by tackling criminal gangs. Interior Minister Suleyman Soylu has filed a criminal complaint against Peker and called for him to be charged with slander.

In his latest video released on YouTube on Sunday and already watched by more than 7 million people, Sedat Peker said his brother was unable to carry out the killing, although Adali was shot dead shortly afterwards in July 1996.

A Turkish investigation did not uncover who was responsible, and the European Court of Human Rights fined Turkey in 2005 for a failure to carry out an “adequate and effective investigation into the circumstances surrounding the killing.”

Peker said the same former minister who wanted Adali killed was responsible for the killings of another journalist, Ugur Mumcu, and the husband of Pervin Buldan, current co-leader of the pro-Kurdish Peoples’ Democratic Party (HDP).

Mumcu’s family called on Sunday for an investigation. Buldan said her husband had been killed by the state and that those responsible were acquitted, adding that she would seek to have them tried again.

Peker, 49, rose to prominence in the 1990s as a gangland figure and was sentenced to 14 years in prison in 2007 for crimes including forming and leading a criminal gang. He has served several jail sentences in Turkey and said last week he is now in Dubai.