Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-402_h315.pdf
Page Number: 32

Cite as:  585 U. S. ____ (2018) 

5 

KENNEDY, J., dissenting 

for long periods of time.  There is no law requiring them to 
do so.  Instead, providers contract with their customers to
collect and keep these records because they are valuable to 
the  providers.  Among  other  things,  providers  aggregate 
the records and sell them to third parties along with other
information gleaned from cell phone usage.  This data can 
be  used,  for  example,  to  help  a  department  store  deter-
mine which of various prospective store locations is likely 
to get more foot traffic from middle-aged women who live 
in  affluent  zip  codes.  The  market  for  cell  phone  data  is 
now estimated to be in the billions of dollars.  See Brief for 
Technology Experts as Amici Curiae 23. 

Cell-site  records  also  can  serve  an  important  investiga-
tive  function,  as  the  facts  of  this  case  demonstrate.    Peti-
tioner, Timothy Carpenter, along with a rotating group of 
accomplices, robbed at least six RadioShack and T-Mobile 
stores  at  gunpoint  over  a  2-year  period.  Five  of  those 
robberies occurred in the Detroit area, each crime at least 
four miles from the last.  The sixth took place in Warren, 
Ohio, over 200 miles from Detroit. 

The  Government,  of  course,  did  not  know  all  of  these 
details in 2011 when it began investigating Carpenter.  In 
April  of  that  year  police  arrested  four  of  Carpenter’s  co-
conspirators.    One  of  them  confessed  to  committing  nine 
robberies  in  Michigan  and  Ohio  between  December  2010 
and  March  2011.    He  identified  15  accomplices  who  had 
participated  in  at  least  one  of  those  robberies;  named 
Carpenter as one of the accomplices; and provided Carpen-
ter’s  cell  phone  number  to  the  authorities.    The  suspect
also  warned  that  the  other  members  of  the  conspiracy 
planned to commit more armed robberies in the immediate 
future. 

The  Government  at  this  point  faced  a  daunting  task.
Even if it could identify and apprehend the suspects, still
it had to link each suspect in this changing criminal gang 
to specific robberies in order to bring charges and convict.