Johannesburg – Democratic Alliance leader Mmusi Maimane hopes a more united caucus will emerge after a special sub-committee looks into tensions within the party in the City of Cape Town.This after DA Mayor Patricia de Lille and mayoral committee member for safety, security and social services JP Smith were placed on special leave on Tuesday, over a spat involving the "shutting down" of the City’s special investigations unit (SIU).Smith had overseen the unit.ALSO READ - BREAKING: De Lille and Smith placed on special leave over spat - DAOver the last week it emerged that De Lille had pushed for the unit to be shut down. When trying to find out why, via a submission to Maimane in August, Smith had questioned whether corruption claims relating to De Lille had anything to do with this.A special sub-committee of the DA’s federal executive was convened by Maimane and started its hearings on Tuesday into the political management of the City of Cape Town.De Lille and Smith were placed on special leave from party activities, and this would not affect their roles in the City’s government.'High accountability'"The reason why the suspension is [from party activities], is to deal with the workings of the party, and not the workings of the City. The City has done its [due] processes on how it deals with the SIU, I have to deal with the internal working of the DA," Maimane said on the sidelines at the Joburg Indaba.Maimane said the purpose of the special committee he had convened was to work towards a "much more united, much more effective" caucus.READ: DA blocks ANC presentation on De Lille's security upgradesHe believed the DA was growing and, as such, the party needed to ensure it kept its values intact."Our job is, as we’re growing, to keep the principles intact… The DA is the only place of high accountability, regardless of what position you’re in."Maimane said the special investigations unit had not been shut down, but had a different way of operating.The City of Cape Town has also said the unit now has a different mandate, however, News24 has in its possession emails between City officials which show that De Lille wanted the unit shut down.