Oops — I missed this one on FourthAmendment.com the other day:
A Magistrate Judge of the Western District of Texas issues an opinion summarizing five years of case law to guide applications for cellular site location information (“CSLI”). In re United States for an Order: Authorizing the Use of a Pen Register and Trap and Trace Device, 2010 U.S. Dist. LEXIS 77319 (W.D. Tex. July 29, 2010).
(From the opinion:)
What is the significance of the conclusion that a cell phone acts as a tracking device when it transmits information about its location? The significance is that if cell phones squarely meet the definition of “tracking devices” it is time to stop treating them as something else, at least when the Government seeks to use them to track a person’s movements. Rule 41 contains express procedures governing tracking device warrants, and those procedures need to be followed with regard to future requests for CSLI. This means several things. First, in past applications, the Government has taken the position that it has no obligation to provide notice of the tracking to the cell phone user, as its notice obligation was met by service of the order on the telecommunications provider from whom it received the CSLI. This does not meet the requirements of Rule 41, which provides that when a tracking device warrant is authorized, “the officer must serve a copy of the warrant on the person who was tracked or whose property was tracked.” FED. R. CRIM. P. 41(f)(2)(C). 19 Thus, warrants seeking CSLI must meet this obligation of Rule 41. Similarly, a return must be filed, as with all other warrants. FED. R. CRIM. P. 41(f)(2)(B).
Read more on FourthAmendment.com.