Advocate HS Phoolka resigned from the Aam Aadmi Party on Thursday, however, he did not disclose any reasons.
"I have resigned from AAP & handed over resignation to Kejriwal ji today," Phoolka said in a tweet.
Phoolka also said that the Delhi Chief Minister asked him not to resign but he (Phoolka) insisted.
The senior lawyer said he would hold a media briefing tomorrow at 4pm at Press Club to explain the reason for leaving the party and share his further plans.
Phoolka had last year resigned as legislator in the Punjab Assembly, expressing unhappiness over the state government's alleged "failure" to initiate action against former chief minister Parkash Singh Badal and retired DGP Sumedh Singh Saini in sacrilege incidents.
He is fighting the 1984 anti-Sikh riots cases, representing victims in the case.