"#AAP can't explain the failure of its due diligence but I have to ask has the party been set up?" Omar wrote on micro-blogging site Twitter.
The National Conference (NC) working president said Arvind Kejriwal led party's "much hyped" vetting process was a "total sham".
"AAP has been set up, no doubt about it. AAP's much hyped vetting process a total sham is also now in no doubt," Omar said in another tweet.