A fugitive secret eyewitness and defendant in the conspiracy case involving the Ayhan Bora Kaplan criminal gang was captured on the Hungarian border upon the initiatives of Turkish intelligence and the Interior Ministry, security sources said Thursday.

The National Intelligence Organization (MIT) located Serdar Sertçelik, the wanted eyewitness, in Montenegro and shared his location with the Justice Ministry, sources said.

An Interpol Red Notice was then issued to arrest Sertçelik, who immediately fled to Hungary through the land route via Serbia.

He was detained using a fake Georgian passport on the Hungarian border, the security sources said, adding that the Justice Ministry has launched legal proceedings for the extradition of the suspect.

Sertçelik was detained in an investigation into a criminal gang led by underworld figure Ayhan Bora Kaplan who was captured last year. Authorities, however, recently uncovered a plot involving Sertçelik. Several police officers were accused of employing him as an "eyewitness" to start a false graft probe to implicate people close to the government, from a former justice minister to prominent politicians. An investigation found that Sertçelik violated the rules of his house arrest several times and then fled Türkiye.

M.I., an inspector working in the organized crime unit of Turkish police, coordinated Sertçelik’s escape with the assistance of three civilians detained earlier this month. He reportedly gave a ride to Sertçelik from Ankara to Istanbul and oversaw his trip from Istanbul to Bodrum in southwestern Türkiye. From Bodrum, Sertçelik crossed to the nearby Greek island of Kos.

Prior to that, he was among police officers who allegedly went against regulations and met the lawyer of Kaplan though his interrogation was already concluded. An investigation found that M.I., the lawyer and other officers had dinner and visited a massage parlor.

The allegations were eerily similar to a plot by the Gülenist Terror Group (FETÖ), which utilized its infiltrators in law enforcement and the judiciary to attempt to topple the government in 2013 by fabricated allegations against government officials in a graft probe.