Mo. Const. art. I, § 15

That the people shall be secure in their persons, papers, homes, effects, and electronic communications and data, from unreasonable searches and seizures; and no warrant to search any place, or seize any person or thing, or access electronic data or communication, shall issue without describing the place to be searched, or the person or thing to be seized, or the data or communication to be accessed, as nearly as may be; nor without probable cause, supported by written oath or affirmation. [Effective - 05 Sep 2014 , see footnote]