1. Any member shall be entitled to creditable prior service within the meaning of sections 104.010 to 104.272 for all service in the United States Army, Navy, or other armed services of the United States, or any women’s auxiliary thereof in time of active armed warfare, if such member was a state employee immediately prior to his or her entry into the armed services and became an employee of the state within ninety days after termination of such service by an honorable discharge or release to inactive status; the requirement of section 104.010 of duties during not less than one thousand forty hours for status as an employee shall not apply to persons who apply for creditable prior service pursuant to the provisions of this section.

2. Any member of the system who served as an employee prior to the original effective date of sections 104.010 to 104.272, but was not an employee on that date, shall be entitled to creditable prior service that such member would have been entitled to had such member become a member of the retirement system on the date of its inception if such member has, or hereafter attains, one year of continuous membership service.

3. Any employee who completes one continuous year of creditable service in the system shall receive credit for service with a state department, if such service has not otherwise been credited.

4. Any member who had served in the Armed Forces of the United States prior to becoming a member, or who is otherwise ineligible pursuant to subsection 1 of this section or other provisions of this chapter, and who became a member after his or her discharge under honorable conditions may elect, prior to retirement, to purchase all of his or her creditable prior service equivalent to such service in the Armed Forces, but not to exceed four years, if the member is not receiving and is not eligible to receive retirement credits or benefits from any other public or private retirement plan for the service to be purchased, and an affidavit so stating shall be filed by the member with the retirement system. However, if the member is eligible to receive retirement credits in a United States military service retirement system, the member shall be permitted to purchase creditable prior service equivalent to his or her service in the armed services, but not to exceed four years, any other provision of law to the contrary notwithstanding. The purchase shall be effected by the member’s paying to the retirement system an amount equal to what would have been contributed by the state in his or her behalf had the member been a member for the period for which the member is electing to purchase credit and had his or her compensation during such period of membership been the same as the annual salary rate at which the member was initially employed as a member, with the calculations based on the contribution rate in effect on the date of his or her employment with simple interest calculated from date of employment from which the member could first receive creditable service to the date of election pursuant to this subsection. The payment shall be made over a period of not longer than two years, measured from the date of election, and with simple interest on the unpaid balance. Payments made for such creditable prior service pursuant to this subsection shall be treated by the retirement system as would contributions made by the state and shall not be subject to any prohibition on member contributions or refund provisions in effect at the time of enactment of this subsection.

5. Any uniformed member of the highway patrol who served as a certified police officer prior to becoming a member may elect, prior to retirement, to purchase all of his or her creditable prior service equivalent to such service in the police force, but not to exceed four years, if he or she is not receiving and is not eligible to receive credits or benefits from any other public or private retirement plan for the service to be purchased, and an affidavit so stating shall be filed by the member with the retirement system. The purchase shall be effected by the member’s paying to the retirement system an amount equal to what would have been contributed by the state in his or her behalf had he or she been a member of the system for the period for which the member is electing to purchase credit and had his compensation during such period been the same as the annual salary rate at which the member was initially employed as a member, with the calculations based on the contribution rate in effect on the date of his or her employment with simple interest calculated from the date of employment from which the member could first receive creditable service to the date of election pursuant to the provisions of this section. The payment shall be made over a period of not longer than two years, measured from the date of election, and with simple interest on the unpaid balance. Payments made for such creditable prior service pursuant to the provisions of this section shall be treated by the retirement system as would contributions made by the state and shall not be subject to any prohibition on member contributions or refund provisions in effect at the time of enactment of this section.

6. Any member of the system under section 104.030 or 104.170 who is an active employee and who served as a nonfederal full-time public employee in this state prior to becoming a member may elect, prior to retirement, to purchase all of his or her creditable prior service equivalent to such service, but not to exceed four years, if he or she is not receiving and is not eligible to receive credits or benefits from any other public plan for the service to be purchased. The purchase shall be effected by the member’s paying to the retirement system an amount equal to what would have been contributed by the state in his or her behalf had he or she been a member of the system for the period for which the member is electing to purchase credit and had his compensation during such period been the same as the annual salary rate at which the member was initially employed as a member, with the calculations based on the contribution rate in effect on the date of his or her employment with simple interest calculated from the date of employment from which the member could first receive creditable service to the date of election pursuant to the provisions of this section. The payment shall be made over a period of not longer than two years, measured from the date of election, and with simple interest on the unpaid balance. Payments made for such creditable prior service pursuant to the provisions of this section shall be treated by the retirement system as would contributions made by the state and shall not be subject to any prohibition on member contributions or refund provisions in effect at the time of enactment of this section. All purchase payments under this subsection must be completed prior to retirement or prior to termination of employment. If a member who purchased creditable service under this subsection dies prior to retirement, the surviving spouse may, upon written request, receive a refund of the amount contributed for such purchase of such creditable service. The surviving spouse shall not be eligible for a refund under this subsection if he or she is entitled to survivorship benefits payable under section 104.140. A member who is entitled to a deferred annuity under section 104.035 shall be ineligible to purchase service under this subsection.