The three civilians, aged between 27 and 42, were found dead on December 22.
Their relatives and political leaders have alleged that the three died due to “custodial torture” as they were among the eight people picked up by the Army for questioning.
A thorough investigation has been ordered into it (the deaths of the civilians) as part of the standard operating procedure, the people cited above said.
The Jammu and Kashmir police are also probing the deaths.
The Army on Saturday said it stands committed to extending “full support and cooperation” in the conduct of investigation.