How many (a) cases of fraud and corruption in the Expanded Public Works Programme did his department investigate in the (i) 2012-13, (ii) 2013-14, (iii) 2014-15 and (iv) 2015-16 financial years, (b) of the specified cases involved ward councillors, (c)(i) criminal charges were laid and (ii) cases were successfully prosecuted and (d) ward councillors were subsequently removed from their positions in each specified financial year?