A Daesh terrorist arrested by Istanbul police in September was a follower of senior Daesh terrorist Abdulgadir Masharipov who killed 39 people in a ruthless attack in Istanbul's Reina nightclub during New Year's Eve, police investigation has found.

According to security sources, the suspect identified as Otobek R. had direct links to Masharipov and referred to him as the "commander."

Otobek R., a 25-year-old Afghan national was reportedly detained by counter-terror squads in Istanbul's Küçükçekmece district. His landlord was also detained in the same operations, but was later released after police determined that he had no links to the terrorist group.

Reports noted that Otobek R. threw a mobile phone out of the window during raids, but police were able to recover the data inside the phone after two-weeks of technical work by the cyber-crimes unit.

Visuals of various sites in Istanbul were reportedly found in the suspect's phone, which were thought to be sent to Daesh terrorists in Syria.

Police also obtained messages sent to Masharipov by Otobek R., which revealed that the two terrorists had met and received training in a Daesh camp in Afghanistan.

Uzbek-born terrorist Masharipov was captured 16 days after Reina attack and was transferred to a high-security prison complex in Istanbul's Silivri district.

Turkey has stepped up its fight against terrorist groups, including Daesh and PKK, and has arrested and detained thousands of suspects planning attacks.

Since the terrorist group's emergence, Turkey has detained over 5,000 suspects and last year launched Operation Euphrates Shield to back Syrian opposition groups fighting Daesh in Syria. The country has deported over 5,000 Daesh suspects and prohibited the entry of over 53,000 terrorist suspects so far.