The missing man was an employee of the KWSB who went missing in 2011.
Dr Farooq Sattar says they will cooperate in murder investigations.
To resolve matters of namaloom afrad, Aafia Siddiqui and terrorism, 3 task forces will submit reports in 2 weeks.
Says MQM chief has said he would accept the court decision.
Says he might not be a leader in the eyes of the international community but he is one for the people of Pakistan.
Hussain, 52, is said to be a close relative of a top Pakistani politician.
The name of the suspect was revealed to be Iftikhar Hussain.
The search operation continued for over 55 hours.
The police had raided two houses in the same area on June 18.
A Pakistani-British was also interrogated in relation to the case.