Mo. Rev. Stat. § 573.052
Upon receipt of any information that child pornography as defined in section 573.010 is contained on a website, the attorney general shall investigate such information. If the attorney general has probable cause to believe the website contains child pornography, the attorney general shall notify a website operator of any child pornography site residing on that website operator's server, in writing. If the website operator promptly, but in no event longer than five days after receiving notice, removes the alleged pornography from its server, and so long as the website operator is not the purveyor of such child pornography, it shall be immune from civil liability. If the website operator does not promptly remove the alleged pornography, the attorney general may seek an injunction pursuant to section 573.070 to remove the child pornography site from the website operator's server. This section shall not be construed to create any defense to any criminal charges brought pursuant to this chapter.
§ 573.052, RSMo