Mishra, who is on an indefinite hunger strike, is demanding that the Aam Aadmi Party (AAP) divulge details of foreign tours undertaken by five leaders of the party.
Mishra was sacked as a minister and from the primary membership of the party after he accused Kejrwal of accepting bribes and being involved in a land scam.
Ankit claimed he was an AAP member and said he attacked Mishra for harming the party.
Sacked Water Minister Kapil Mishra's "satyagraha" fast to protest corruption in the AAP was on Wednesday marked by high drama as he was slapped by a young man.
The attacker, who has been identified as Ankit Bhardwaj, allegedly ran over to Mr. Mishra and hit him on his neck before he was pulled aside by Mishra's supporters. "Government officials are sending information to me", Mishra claimed. "I will continue to sit on hunger strike till details of worldwide travel expenses of five AAP leaders are shared", he had said. "It was nearly as if the party was waiting for something like this to happen", Mishra wrote.
Earlier this morning, Mishra's mother had written a letter to Chief Minister Arvind Kejriwal, accusing him of spreading lies about her son. "When his hand moved forward during the discussion with Mishra, it was construed as an assault", a senior police officer said. Sources said that presently he was working in one of the mohalla clinics of minister Satyendra Jain.
He claimed that the details of the foreign trips by AAP leaders would "reveal a lot" about alleged corruption by them.
Mishra has alleged that the investigation into the tanker scam was repeatedly delayed and influenced by Kejriwal and "his two men".
Soon after, Praveen Shankar Kapoor, media in-charge of Delhi BJP, said that no BJP Yuva Morcha worker was involved in any such incident.
The Kejriwal-led AAP government had in June 2015 constituted a fact-finding committee to go into the alleged irregularities in procurement of some 385 stainless steel water tankers by the DJB.