Write SQL query to solve given problem: What is the fax number for the district with the most number of crimes in January, 2018?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T1.fax FROM District AS T1 INNER JOIN Crime AS T2 ON T1.district_no = T2.district_no WHERE T2.date LIKE '%1/2018%' GROUP BY T2.district_no ORDER BY COUNT(case_number) DESC LIMIT 1