Write SQL query to solve given problem: Who are the officers involved in cases that are voted as 'No Bill'. List their last name and gender.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T2.last_name, T2.gender FROM incidents AS T1 INNER JOIN officers AS T2 ON T1.case_number = T2.case_number WHERE T1.grand_jury_disposition = 'No Bill'