Mo. Rev. Stat. § 9.120: Week of May 15, Peace Officers Memorial Week.

May fifteenth of every year shall be known and designated as "Missouri's Peace Officers Memorial Day", and the week in which that date falls shall be known and designated as "Missouri's Peace Officers Memorial Week". It shall be a day and week on which to commemorate the sacrifices of the federal, state, county and municipal peace officers who have been killed or disabled in the performance of their duties. The United States flag and the Missouri state flag shall be flown at half-staff on all government buildings on Missouri's peace officers memorial day.