Turkish authorities are looking into possible financial motives behind a gunman's deadly attack on a nightclub in Istanbul as about $150, 000 believed to be belonging to the militant were seized, the media reported on Monday.

The money was found in an operation launched by the security forces at an apartment in the outlying district of Silivri on January 5, Xinhua news agency reported.

Police determined that the money could not be delivered to the attacker due to strict security measures enforced in the wake of the attack on Reina nightclub early on New Year's day, in which 39 persons died.

A manhunt continues as the gunman managed to escape following the shooting spree, for which the Islamic State (IS) militant group has claimed responsibility.
 

In light of the cash seizure, police believe the militant launched the attack for financial gains rather than usual ideological reasons behind most of the IS assaults.

The Turkish authorities are also looking into possible roles of secret services in the attack.

Turkish police have identified the attacker as Abdulgadir Masharipov, a man of Uzbek origin who is also known as Abu Muhammed Horasan.