Who is the commanding officer in the district with the highest number of reported crimes where no arrest has been made?
where no arrest refers to arrest = 'FALSE'; highest number of crime refers to Max(Count(report_no)); commanding officer refers to commander
SELECT T2.commander FROM Crime AS T1 INNER JOIN District AS T2 ON T1.district_no = T2.district_no WHERE T1.arrest = 'FALSE' GROUP BY T2.commander ORDER BY COUNT(T1.report_no) DESC LIMIT 1