"We are dealing with a situation", a senior police office told AFP on condition of anonymity.
The video of Dar tied to a jeep follows others posted to social media showing Indian security forces harassed and assaulted by civilians.
In the backdrop of students protests in the valley, university exams have been postponed and broadband services have been suspended.
Farooq Ahmad Dar, a 24-year-old shawl weaver, was picked up by soldiers near his house after voting in by-elections last week.
He was called "Pak supporter", people wished him to be "kicked, beaten and humiliated on the streets of Kashmir", and was accused of being even "stupider than Gurmehar" (a slain army officer's daughter who had spoken up for students' right to protest).
Army spokesman Lieutenant Colonel Rajesh Kalia said the video's authenticity was being ascertained, adding, "Action will be taken against those found guilty of misconduct".
Jammu [Jammu and Kashmir], India: Jammu and Kashmir Deputy Chief Minister Nirmal Singh on Monday brushed aside a National Conference (NC) demand for imposition of governor's rule in the state and asserted that the PDP-BJP government will combat the existing situation.
Eight people were killed in clashes with security forces following the April 9 by-election in Srinagar, where the voter turnout was just 7.14 per cent, the worst in years.
Talking to NDTV, Rohatgi said: "The recent report about a stone pelter tied to an Army vehicle, it helped contain stone-pelters and saved the poll officials. What is different now is that this case has been documented, thanks to social media". The killing triggered a round of violent protests in which more than 100 people were killed and scores blinded as security forces used pellet guns on stone-throwing protesters.
According to Reuters, militants had also stepped up their attacks in Kashmir by raiding the homes of police officers. In another video, a group of workers from the ruling political party of the state reportedly renounced mainstream politics.
Pro-independence leaders blame India for denying the Kashmiri people the right to self-determination promised to them by the worldwide community through numerous UN Security Council resolutions. Both claim the territory in its entirety.
Admitting that the situation in Kashmir Valley was deteriorating, authorities are apprehensive that this summer too will be "hot" like a year ago when mass protests marred life in the State for more than five months following the killing of Hizbul Mujahideen terrorist Burhan Wani in an encounter in June.