The probe will be conducted by a retired judge, Haryana Additional Chief Secretary Devender Singh told the media in Karnal.
Locked in a showdown with the Haryana government over the lathi-charge, the farmers squatted at the gates of the mini-secretariat on Tuesday evening after talks with the local administration failed.
The BSP will always stand with the genuine demands of the protesting farmers, and the party has been raising its voice for them both inside and outside Parliament, BSP chief Mayawati said.
The party said when Prime Minister Narendra Modi was inaugurating the renovated Jallianwala Bagh complex in Amritsar, a second Jallianwala Bagh was happening in Haryana.
Rahul Gandhi shared a picture on Twitter of a farmer with blood-soaked clothes after the lathicharge and said the image has shamed India.
More farmers later gathered at the police line area at Ambala City and demanded release of all those who had been detained, including one of their leaders.
Police personnel were deployed and barricades were also put to prevent farmers from going towards the meeting hall.
According to the official release, the decision was taken on the instructions of Chief Minister Manohar Lal Khattar.
The Haryana government said it will provide two hours of additional power supply to farmers for sowing paddy due to delay in monsoon.
At the protest site at Khatkar toll plaza, 500-700 protesters usually gather during the day, while only a few stay there overnight, according to the police.
Twenty policemen, including five women officials, were injured in the clash between the farmers and the police on Sunday, officials said.
The farmers have been protesting at different borders of the national capital since November 26 last year against the farm laws passed by the Centre.
Farmer leaders have said road and rail transport will be blocked and claimed that markets will also remain closed.