The DA says it has identified a third councillor who helped unseat the party in Johannesburg last year by voting for Geoff Makhubo.According to the party's caucus leader, Funzela Ngobeni, councillor Anthony Still would be undergoing a disciplinary hearing.In December, three DA councillors voted for Makhubo for the position of mayor, helping to unseat the party in Johannesburg.Two of the three were booted from the party earlier this month and until now, the third was still unknown.According to Ngobeni, Still had revealed his allegiance when a Johannesburg caucus meeting collapsed on Thursday.The DA walked out of the meeting but Still was the only member to remain behind."All of us walked out, but he refused to walk out, and he stayed there alone. That confirms he is the third one working with the ANC," Ngubeni said.He said this was a show of solidarity for the opposition.But Still has denied that he voted against the DA. Speaking to News24, Still said staying behind at the caucus meeting did not mean he previously voted against the DA."[Ngubeni] can't join the dots between that [not walking out] and who didn't or did vote for Makhubo, that's unrelated.... He can think whatever he likes, I didn't actually vote for Makhubo," Still said. "This I deny categorically. It is just untrue."He said there was no evidence that it was a DA member who voted for Makhubo and it "could quite possibly be anyone else". "Further, there is no evidence that three DA councillors broke ranks on that vote. There are other plausible explanations for the third vote," he said. Still said he did not walk-out with his party members during the caucus meeting because he disagreed with the DA's take on the legitimacy of the council speaker."I did defy a caucus instruction to vacate the chambers during the council meeting [on Thursday] 30th January. This had to do with the view of the legitimacy or otherwise of the speaker and is a separate matter to the December vote. "Cllr Ngobeni has no basis on which to conflate the two issues," Still said.