Law firm Slater & Gordon yesterday launched a further class action against the Centro Property Group (CNP.AX), adding to an existing class action the firm is running against the group. The new case includes only those investors who acquired Centro shares after PricewaterhouseCoopers was appointed as auditor to Centro in 2007. The move follows a ruling last month that all claimants in a class action must have a claim against every defendant in the case.