Shakeel Yusuf, who works as a medical assistant at Srinagar's Sher-i-Kashmir Institute of Medical Sciences, appeared before the agency along with five others suspected to have received funds from Salahuddin, they said.
The NIA wanted to question him over allegations that he used to receive funds sent by his father through a US-based international wire transfer company, officials said.
The agency alleged that Yusuf was also "one of several Indian contacts" of a hawala operator based in Saudi Arabia identified as Aijaz Ahmed Bhat, and was alleged to have been in telephonic contact with him for receiving money transfer codes.
Yusuf may be quizzed again, officials said.
The case, registered by the NIA in April 2011, relates to the transfer of money from Pakistan to Jammu and Kashmir through hawala channels via Delhi, which the agency believed was used in funding terrorism and secessionist activities.
The NIA has so far filed two charge sheets against six people including G M Bhat, a close aide of pro-Pakistan separatist Syed Ali Shah Geelani, Mohammed Siddiq Ganai, Ghulam Jeelani Liloo and Farooq Ahmed Dagga. All four are in judicial custody.