In a province-wide operation on Wednesday, police in Afyon detained 37 suspects linked to the Gülenist Terror Group (FETÖ) and discovered a digital archive of personal data belonging to 49 million people.

A police spokesman said that the archive was apparently 2009 records of the official voter registration database and they have launched an investigation on how the suspects got a hold of it.

The operations in 28 locations across Afyon targeted "gaybubet" (absence) houses run by the terrorist group, which is blamed for the July 15, 2016 coup attempt that killed 250 people.

Authorities say the group, known for its high level of secrecy, uses safe houses to hide wanted members. Among the detained suspects, 21 had arrest warrants while the others are accused of aiding and abetting them. Police also found fake IDs, a large number of cellphones, cash and equipment to make forged IDs. One of the unidentified suspects who was taken into custody was the group's "provincial imam" (a term the group uses to refer to its point men), according to media outlets.

Since December 2013, when the terrorist group emerged as the perpetrator of two coup attempts, FETÖ has been regarded as a security threat. Prosecutors claim that the group's infiltrators in law enforcement, the judiciary, bureaucracy and the military had waged a long-running campaign to topple the government. The group is also implicated in a string of cases related to its alleged plots to imprison its critics, money laundering, fraud and forgery. As its activities face heightened scrutiny following multiple attempts to seize power, FETÖ apparently strove to hide its fugitive followers, according to its former followers.