Oregon Revised Statutes Procedure in Criminal Matters Generally § 133.693

(1) Subject to the provisions of subsection (2) of this section, in any proceeding on a motion to suppress evidence the moving party shall be entitled to contest, by cross-examination or offering evidence, the good faith, accuracy and truthfulness of the affiant with respect to the evidence presented to establish probable cause for search or seizure.

(2) If the evidence sought to be suppressed was seized by authority of a search warrant, the moving party shall be allowed to contest the good faith, accuracy and truthfulness of the affiant as to the evidence presented before the issuing authority only upon supplementary motion, supported by affidavit, setting forth substantial basis for questioning such good faith, accuracy and truthfulness.

(3) In any proceeding under subsection (2) of this section, the moving party shall have the burden of proving by a preponderance of the evidence that the evidence presented before the issuing authority was not offered in good faith, was not accurate and was not truthful.

(4) Where the motion to suppress challenges evidence seized as the result of a warrantless search, the burden of proving by a preponderance of the evidence the validity of the search is on the prosecution.

(5) The court shall determine whether, under applicable law, any inaccuracy, untruthfulness or lack of good faith requires suppression.