Warrant to track a communications device
Wis. Stat. § 968.373
in effect(1) Definition. In this section, “communications device” includes any wireless or mobile device that transmits wire or electronic communications.
(2) Prohibition. Except as provided in sub. (8), no investigative or law enforcement officer may identify or track the location of a communications device without first obtaining a warrant under sub. (4).
(3) Application for warrant. Upon the request of a district attorney or the attorney general, an investigative or law enforcement officer may apply to a judge for a warrant to authorize a person to identify or track the location of a communications device. The application shall be under oath or affirmation, may be in writing or oral, and may be based upon personal knowledge or information and belief. In the application, the investigative or law enforcement officer shall do all of the following:
(a) Identify the communications device.
(b) Identify, if known, the owners or possessors of the communications device.
(c) Identify, if known, the person who is the subject of the investigation.
(d) Provide a statement of the criminal offense to which the information likely to be obtained relates.
(e) Provide a statement that sets forth facts and circumstances that provide probable cause to believe the criminal activity has been, is, or will be in progress and that identifying or tracking the communications device will yield information relevant to an ongoing criminal investigation.
(4) Warrant. A judge shall issue a warrant authorizing a person to identify or track the location of a communications device if the judge finds that the application satisfies the requirements under sub. (3). A warrant issued under this subsection may not authorize the action for a period that exceeds 60 days. A judge may extend the authorized period upon the request of the attorney general or a district attorney if the request satisfies the requirements under sub. (3). Each extension may not exceed 60 days but there is no limit on the number of extensions a judge may grant.
(4m) Secrecy. A warrant under sub. (4) shall be issued with all practicable secrecy and the request, application, or other information upon which the warrant is based may not be filed with the clerk or made public until the warrant has been executed and returned to the court. The judge may issue an order sealing the application, request, or other information upon which the warrant is based. The judge may issue an order prohibiting any person who has been ordered by the judge to provide assistance to the applicant from disclosing the existence of the warrant or of the investigation to any other person unless ordered by a judge.
(5) Assistance. Upon the request of the attorney general, a district attorney, or a law enforcement agency authorized by a warrant issued under sub. (4) to track or identify the location of a communications device, the court shall order a provider of electronic communication service or other person to provide to an investigative or law enforcement officer information, facilities, and technical assistance to identify or track the location of the communications device. A person who is ordered under this subsection to provide assistance shall be compensated for the reasonable expenses incurred.
(6) Confidentiality of information.
(a) Information obtained under this section regarding the location of a communications device is not subject to the right of inspection and copying under s. 19.35 (1).
(b) The attorney general, a law enforcement agency, or a district attorney that obtains under this section information regarding the location of a communications device, or evidence derived from the information, shall destroy any information or evidence derived from it if the trial court reaches final disposition for all charges in connection with the investigation that was the subject of the warrant under sub. (4) and no person was adjudged guilty of a crime in connection with the investigation.
(c) Information regarding the location of a communications device that is obtained under this section may be disclosed to other investigative or law enforcement officers.
(6m) Return. A warrant issued under sub. (4) shall be returned, including in the form of a summary description of the information received, to the court not later than 5 days after the records or information described in the warrant are received by the attorney general, district attorney, or law enforcement agency, whichever is designated in the warrant.
(7) Defense and immunity.
(a) A person on whom a warrant issued under sub. (4) is served is immune from civil or criminal liability for acts or omissions in providing records or information, facilities, or assistance in accordance with the terms of the warrant.
(b) A person who discloses the location of a communications device under sub. (8) (b) is immune from civil or criminal liability for the acts or omissions in making the disclosure in accordance with sub. (8) (b).
(c) No cause of action or criminal action may arise against any provider of electronic communication service, or its officers, employees, or agents or other persons specified in the court order under sub. (5), for providing information, facilities, or assistance in accordance with the terms of a court order under sub. (5).
(7m) Technical irregularities. Evidence disclosed under a warrant issued under sub. (4) may not be suppressed because of technical irregularities or errors not affecting the substantial rights of the defendant.
(8) Exception.
(a) The prohibition in sub. (2) does not apply to an investigative or law enforcement officer who identifies or tracks the location of a communications device if any of the following applies:
1. The customer or subscriber provides consent for the action.
2. An emergency involving danger of death or serious physical injury to any person exists and identifying or tracking the location of the communications device is relevant to preventing the death or injury or to mitigating the injury.
(b) A provider of electronic communication service shall disclose the location of a communications device without a warrant if any of the following applies:
1. The customer or subscriber provides consent for the particular disclosure.
2. The provider of electronic communication service believes in good faith that an emergency involving the danger of death or serious physical injury to any person exists and that disclosure of the location is relevant to preventing the death or injury or to mitigating the injury.
3. The provider of electronic communication service receives a written request from a law enforcement agency attesting that the disclosure of device location information is needed to allow a law enforcement agency to respond to a call for emergency services or to an emergency situation that involves the danger of death or serious physical injury to any person and disclosure of device location information is necessary to prevent or mitigate that danger.
(c) If the location of a communications device is disclosed to a law enforcement agency under par. (b) 2. or 3., the provider of electronic communication services shall notify the customer or subscriber of the information disclosure within 30 days after the call for emergency services or the emergency situation, or when any case that resulted from the call for emergency services or the emergency situation has resolved, whichever is later.
(8g) Court review. If the location of a communications device is disclosed to a law enforcement agency under sub. (8) (b) 2. or 3. and evidence of criminal activity was obtained as a result of the disclosure, the law enforcement agency shall, within 3 days of the disclosure, apply to a judge for an order retroactively authorizing the emergency disclosure. The application under this subsection shall set forth the facts giving rise to the emergency disclosure, and the judge shall promptly issue an order determining whether the emergency disclosure was necessary. If the judge determines that the disclosure was not necessary, the judge shall order that the evidence be suppressed in any criminal proceeding on the grounds that the evidence was unlawfully obtained, and order immediate notification under sub. (8) (c).
(8m) Jurisdiction. For purposes of this section, a person is considered to be doing business in this state and is subject to service and execution of process from this state, if the person makes a contract with or engages in a terms of service agreement with any other person, whether or not the other person is a resident of this state, and any part of the performance of the contract or provision of service takes place within this state on any occasion.
(8s) Emergency contact information. Any provider of electronic communication services considered to be doing business in this state under sub. (8m) shall submit its emergency contact information to the department of justice to facilitate a request for information made by a law enforcement agency or tribal law enforcement agency under this section no later than May 28, 2024, annually by January 1 of each year thereafter, and as soon as possible any time a change occurs to the emergency contact information most recently submitted to the department of justice.
(9) Seizure. Any device used in violation of sub. (2) may be seized as contraband by any law enforcement officer and forfeited to this state in an action under s. 973.075.
Source: WI Statutes (Official Site)URL: https://docs.legis.wisconsin.gov/document/statutes/968.373Fetched: 10/7/2026