Turkish security forces caught a Daesh terrorist red-handed as he was secretly observing a command post in Istanbul early Thursday.

Police received a tipoff that a man had climbed up a tree and was spying on the Military Police Command Post in Istanbul’s Yenibosna district at 2 a.m. local time (11 p.m. GMT), Demirören News Agency (DHA) reported.

The suspect, identified as Muhammed Yahya E., was immediately detained.

Police found Daesh-linked images and documents on the suspect, the report said.

He was arrested and sent to jail after procedures, the report added.

Turkey recognized Daesh as a terrorist group in 2013, and has since been attacked numerous times, including 10 suicide bombings, seven bombings and four armed assaults, which have killed 315 people and injured hundreds more.

In response, Turkey launched military and police operations both inside and outside the country, capturing top Daesh members in counterterrorism efforts at home and in Syria.

The terrorist group has been trying to reestablish itself in Turkey after being dealt a heavy blow in Iraq and Syria. According to testimony by terrorists detained in previous operations in Adana province, Daesh had been trying to kidnap judges, prosecutors and tourist groups as ransom in return for Daesh terrorists held in Iraq and Syria.

Turkey detained the ostensible “Turkey emir” of Daesh, named Mahmut Özden, in August. He was planning to carry out an attack on Hagia Sophia Grand Mosque and target politicians, nongovernmental organization (NGO) heads and other prominent figures in Turkey, according to the official investigation.

Police deciphered encrypted messages sent by Daesh ringleaders in Syria and Iraq that included a wide range of instructions, including orders to kidnap tourist groups, prosecutors and deputies, as well as attack Incirlik Air Base in Adana among other plans.