Minn. Stat. § 626A.16: TELEPHONE COMPANY TO AID IN DETECTION.

Subject to regulation by the Minnesota public utilities commission, any telephone or telegraph company shall, upon request of any subscriber and upon responsible offer to pay the reasonable cost thereof, and with the discretion of the carrier; subject, however, to an appropriate court order to furnish whatever services may be within its command for the purpose of detecting any unlawful interception of communications. All such requests by subscribers shall be subject to the provisions of section 626A.05 and the company shall disclose only the existence or absence of interception that is not the subject of a court order under that section. All such requests by subscribers shall be kept confidential unless divulgence is authorized in writing by the requesting subscriber.