New security camera footage has revealed how former police chiefs linked to the Gülenist Terror Group (FETÖ) helped takeover a police headquarters in Ankara on the night of the attempted coup.

The footage that surfaced on Wednesday was taken around 2:12 a.m. local time on July 15. It shows three men, accompanied by others in civilian clothing, later identified to be off-duty police officers, entering police intelligence headquarters in capital Ankara.

Gürsel Aktepe, former deputy director of police intelligence, Lokman Kırcı, former deputy police chief of Ankara and Zeki Taşkın, a former senior official for the intelligence department, are seen heading into the headquarters, without any visible resistance, despite the fact that all three were earlier dismissed from duty for links to the Gülenist terror cult.

After entering, the suspects apparently mouthed orders to others around them to complete the takeover. Messages sent by a senior Gülenist to a FETÖ member who was in charge of police officers loyal to the group have already uncovered how the group mobilized its followers to help the coup troops.

The messages sent on an instant messaging app were found on Taşkın's cellphone. Taşkın, who was arrested along with Aktepe and Kırcılı after the putsch was quelled, had called on fellow Gülenists "to help the troops."

"Stop what you are doing and help the soldiers. Disobey the orders (to stand against the coup). If you see anyone resisting, try to convince them to stop. Inform the retired officers too and tell them to get their guns and go to army headquarters. Whoever is available should go to army headquarters, police headquarters, anti-terror police headquarters. Shoot anyone resisting the coup and help the troops," part of the message read.

Testimony of former police chiefs arrested after the coup attempt shows the terrorist group communicated via an encrypted messaging app as the coup attempt unfolded and convened around the police building. Meanwhile, soldiers linked to FETÖ were moving to capture strategic locations from army headquarters to the Presidential Palace.

Aktepe said in his initial testimony that a former intelligence officer he was acquainted with told him and other former officers in a Tango messaging group to "support" the coup and contact "Gen. Mehmet."

Although Aktepe did not specify who exactly that general was, it is likely Mehmet Partigöç, a brigadier general who worked at the office of the Chief of Staff, charged with being one of planners of the coup attempt. Partigöç was arrested after the foiled coup attempt and was reportedly among the generals who met a senior Gülenist days before the putsch bid to plan it. Aktepe has acknowledged his loyalty to the terrorist cult and said he received "monthly payments" from FETÖ after he was dismissed from duty.

After his capture, Zeki Taşkın said in his initial testimony that Lokman Kırcılı told him that soldiers would go first when he asked him how the coup would proceed.

"A few police intelligence officers checked our IDs when we went there and allowed us in. I also saw some engineers entering the building. I was there because I thought I would take back my post after the coup," Taşkın said.