U.S.-led coalition forces liberated all of the territory ISIS held in Syria and Iraq in the first quarter of 2019. Although the defeat was a significant achievement, ISIS continues its activities outside the Syria and Iraq region. Turkey matters to ISIS because the group carries out attacks and uses the country to move fighters and supplies. However, Turkey relies heavily on police crackdowns to deter terrorism. Drawing on data from the Armed Conflict Event and Location Database, the Turkish Ministry of Interior, and an online news source, the current study first analyzed trends in ISIS attacks around the world. Then, it explored the extent to which police arrests prevent ISIS from further deadly attacks in Turkey. Results from the study suggest that ISIS activities are likely to decrease in Syria and Iraq after the U.S.-led military operations but increase in other countries. Also, mass arrests were ineffective in preventing subsequent deadly attacks in Turkey. Policy implications are discussed.