Local media have reported that TV audience research body TIAK has terminated AGB Nielsen’s contract early, although the company said it has received no confirmation of this.

Seven people were reportedly detained by Istanbul Police’s organised crime bureau as part of the raids, including AGB Nielsen’s production director Hilmi Berkoz and Cemal Orcun Koktuna, who used to work at AGB but is now financial director at TNS Turkey. Four have been released following questioning but three – including Berkoz and Koktuna – are said to have been referred to a court demanding their arrest.

An AGB Nielsen spokesperson told Research: “There were media reports last week alleging fraud in TV audience ratings that referred to a police investigation, Nielsen, and certain of its personnel. The media reports were misleading because they did not clearly indicate that Nielsen had also referred an incident of data theft to the police in September for investigation.

“We are gratified to see the police pursuing its investigation for the benefit of our clients, the TV industry and the general public. Nielsen and its personnel are cooperating with the police investigation but we can’t comment further on it. Nielsen continues to place the highest priority on integrity in its TV audience ratings and its entire management team is dedicated to that objective.”

As reports emerged of the raids, TIAK is reported to have pulled the plug early on its contract with Nielsen – which was to end soon anyway after a new contract was won by TNS.

TIAK chief executive Hidayet Karaca was quoted as saying: “The reliability of the measurement system that constituted the basis for the distribution of advertisements and conducted by [AGB Nielsen] has ceased to be.”

Nielsen said, it has “not received official confirmation of this yet” and it is unclear whether TNS’s contract will now commence sooner than expected. A TNS spokesperson said that the company was “in discussions with TIAK” and that conversations were ongoing, but could not comment further.

TIAK could not be reached for comment.

Allegations about panellists being offered money by TV companies to alter their viewing habits previously surfaced in 2009, when it was claimed that a small number of AGB Nielsen’s 2,500-strong panel had been offered cash to watch certain programmes or switch off during ad breaks. AGB Nielsen and TIAK asked a local prosecutor to investigate the matter.