What are the heights of perpetrators in descending order of the number of people they injured?
SELECT T1.Height FROM people AS T1 JOIN perpetrator AS T2 ON T1.People_ID  =  T2.People_ID ORDER BY T2.Injured DESC
heights of perpetrators refers to T1.Height; descending order of the number of people they injured refers to ORDER BY T2.Injured DESC; joining tables people and perpetrator on People_ID refers to JOIN perpetrator AS T2 ON T1.People_ID  =  T2.People_ID;