The Feast Day of the Archangel Michael is September 29.
Please pray in front of your local police station on that day. If you are Catholic, please pray a Rosary. If you are not Catholic, pray in your faith tradition. Here is a prayer that many say:
St. Michael the Archangel, defend us in battle. Be our defense against the wickedness and snares of the Devil. May God rebuke him, we humbly pray, and do thou, O Prince of the heavenly hosts, by the power of God, thrust into hell Satan, and all the evil spirits, who prowl about the world seeking the ruin of souls. Amen.