Mo. Rev. Stat. § 86.1010
Except as provided in subsection 5 of section 86.1100, the board of police commissioners shall cause to be deducted from the compensation of each member who is accruing creditable service a percentage of such member's compensation as determined by the retirement board, as such member's contribution to the pension fund. The sum so deducted shall be paid by the board of police commissioners promptly after each payroll to the retirement board to be credited to the member's account. Every member shall be deemed to consent to the deductions made and provided for herein. The board of police commissioners shall certify to the retirement board on every payroll the amount deducted, and such amounts shall be paid into the pension fund and shall be credited to the individual pension account of the member from whose compensation such deduction was made.
§ 86.1010, RSMo