Turkish authorities on Monday issued detention warrants for 25 suspects tied to the Gülenist Terror Group (FETÖ) as part of an ongoing investigation.

The suspects are wanted for their role in placing FETÖ members in various public institutions, the Chief Public Prosecutor’s Office in the capital, Ankara, said.

The anti-smuggling police continue operations to apprehend the suspects in 16 provinces, including Ankara, authorities said.

The warrants follow countless others for hundreds of suspects that serve in remnant cells of FETÖ.

Since December 2013, when the terrorist group emerged as the perpetrator of two coup attempts disguised as graft probes, FETÖ has been regarded as a security threat. Prosecutors say 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. A former member who testified to prosecutors has said that the number of the group’s so-called "gaybubet (absence) houses" – used as safe houses – increased from 75 to 560 across Türkiye. Authorities believe that number might be even higher.

FETÖ has been under more intense scrutiny since the July 15, 2016, coup attempt its infiltrators in the army carried out.

The Ministry of National Defense announced last year that 24,387 Turkish Armed Forces (TSK) members were sacked since the coup attempt for possible ties to the group, while administrative inquiries are underway for 781 others.

Meanwhile, an unknown number of FETÖ members, mostly high-ranking figures, fled Türkiye when the coup attempt was thwarted.

Many of the group’s members had already left the country before the coup attempt after Turkish prosecutors launched investigations into other crimes of the terrorist group. Despite Türkiye’s extradition requests and bilateral legal agreements, many FETÖ members still freely enjoy their lives in different countries around the world. In the aftermath of the 2016 coup attempt, Türkiye has sped up extradition processes for members of FETÖ abroad.

The U.S., where FETÖ’s fugitive head, Fetullah Gülen, resides, is the subject of most extradition requests. Türkiye has sent several extradition requests for Gülen to Washington but, unfortunately, has seen little progress on this subject. Gülen, who arrived in the U.S. in 1999, currently lives in a luxurious retreat in Saylorsburg, Pennsylvania.

Ankara formally requested Gülen’s extradition on July 19, 2016, and has been pressing the U.S. ever since, sending hundreds of folders full of evidence implicating Gülen and FETÖ in the coup attempt.

The issue has been raised in bilateral meetings between Turkish and American officials in phone calls, letters and other exchanges.