Police chief: Take no prisoners

Chief Commissar of Israeli police Dudi Cohen commended Jerusalem police on killing the Arab who attacked Merkaz HaRav Yeshiva. Cohen declared that all such perpetrators should be killed. And rightly so, instead of releasing them in prisoners exchanges.
Cohen also asked all Israelis to report on all suspicious people. Since the Arab terrorist was no more suspicious than any other Arab, should we report on all Arabs?