The police's decision was reportedly based on statements of the staff of a cow shelter and mobile phone records.
55-year-old Pehlu from Nuh in Haryana was grievously assaulted by self-styled cow vigilantes near Behror in Rajasthan on the Delhi-Alwar highway on April 1, for being a cattle smuggler.
He succumbed to his injuries at a private hospital on April 3.
"It is a conspiracy against the gau rakshaks. I say this is wrong act against cow vigilantes and it is neither good for the government not the administration," Kamal said.
"I appeal Prime Minister Narendra Modi to take immediate action in this matter," she added.
Earlier in April, a video of the meeting between Kamal and accused Vipin Yadav, held at Yadav's college, showed the former showering praises on the young boy.
In the video, Kamal said, "Don't worry Vipin, the whole of Bharat is with you." Then, she turns to others and continues: "These boys are like (Chandrasekhar) Azad and Bhagat Singh, they have done nothing wrong".(ANI)