SENATE COMMITTEE ON GOVERNANCE AND FINANCE
Senator Robert M. Hertzberg, Chair
2015 - 2016 Regular
Bill No:
Author:
Version:
Consultant:

SB 741
Hill
2/27/15
Weinberger

Hearing Date:
Tax Levy:
Fiscal:

4/15/15
No
No

CELLULAR COMMUNICATION INTERCEPTION TECHNOLOGY

Prohibits a local agency from acquiring or using cellular communications interception
technology without first adopting a resolution or ordinance that meets specified criteria.

Background and Existing Law
Some California sheriff’s offices and police departments are using surveillance devices that
allow investigators to gather cellphone signals to pinpoint a suspect’s location. By simulating a
cellular communications tower’s functions, these devices force all cell phones within the vicinity
to transmit information to the devices. The information that these devices can collect reportedly
includes a cell phone’s number, a phone’s unique “International Mobile Subscriber
Identification” (IMSI) number, its electronic serial number, the location of the most recent cell
tower the phone connected with, and phone numbers dialed from the cell phone. Some reports
indicate that the devices can accurately identify a cell phone’s location, even if the phone is
turned off, and could be modified to capture the content of calls or text messages from a phone.
These devices are known as “IMSI catchers” and sometimes referred to by brand names like
“StingRay” or “HailStorm.”
Exact information about how IMSI catchers work and what they can do is difficult to obtain.
Local law enforcement agencies’ acquisition and use of these devices is apparently subject to
non-disclosure requirements that, according to various sources, are imposed by the devices’
manufacturer, the Federal Bureau of Investigation, or both, to prevent the release of information
that could compromise the devices’ effectiveness. Public information requests for documents
relating to the devices are either denied or reveal only heavily-redacted materials. Some news
reports indicate that local law enforcement authorities even refuse to reveal information about
IMSI catchers to elected officials who are considering whether to approve the acquisition and use
of the devices by a sheriff or police department.
IMSI catchers are reportedly used by at least 11 local law enforcement agencies in California
including Alameda County, Los Angeles County, the City of Los Angeles, Sacramento County,
San Bernardino County, the City of San Diego, the City and County of San Francisco, and the
City of San Jose. On February 24, 2015, the Santa Clara County Board of Supervisors
authorized the Sheriff’s Office to use funding from the State Homeland Security Grant Program
to procure a “mobile phone triangulation system,” presumably an IMSI catcher.
The secrecy surrounding this technology raises substantial unanswered questions about the
privacy and civil liberties implications of these devices, particularly because IMSI catchers

 SB 741 (Hill) 2/27/15

Page 2 of 3

collect information from the phones of anyone in the devices’ vicinity, not just individuals
targeted by law enforcement.
Some local officials want the public to have more information about the use of cellular
communication surveillance devices in their communities.
Proposed Law
Senate Bill 741 prohibits a local agency from acquiring or using cellular communications
interception technology unless the agency’s legislative body adopts an authorizing resolution or
ordinance. The authorizing resolution or ordinance must:
Be adopted at a regularly scheduled public meeting of the legislative body at which
members of the public are afforded a reasonable opportunity to comment upon the
proposed resolution or ordinance;
Set forth the local agency’s policies as to the circumstances when cellular
communications interception technology may be employed; and,
Set forth usage and privacy policies, which must include how data obtained through use
of the technology is to be used, protected from unauthorized disclosure, and disposed of
once it is no longer needed.
SB 741 defines “cellular communications interception technology” as any device that intercepts
mobile telephony calling information or content, including an international mobile subscriber
identity catcher or other virtual base transceiver station that masquerades as a cellular station and
logs mobile telephony calling information.
SB 741 defines “local agency” as any city, county, city and county, special district, authority,
community redevelopment agency, or other political subdivision of the state, including every
county sheriff and city police department.
The bill requires that the cellular communications interception technology usage and privacy
policies must be posted conspicuously on an agency’s Internet Web site, if the Agency maintains
an Internet Web site.
State Revenue Impact
No estimate.
Comments
1. Purpose of the bill. Because of the non-disclosure agreements that law enforcement officials
have used to justify the secrecy surrounding IMSI catchers, the public and their elected
representatives know very little about this technology. Some of the unanswered questions about
IMSI catchers raise fundamental civil liberty and privacy concerns that deserve to be considered
by the public. Important questions that merit public consideration include:
What data is gathered from the phones of third-parties who are unrelated to the purpose
for which an IMSI catcher is deployed? Is that data stored for any period of time? Who
can access it? How is it used? Is it secured against unauthorized access?

 SB 741 (Hill) 2/27/15

Page 3 of 3

Can IMSI catchers be modified to capture voice and text content from cell phones? Can
law enforcement agencies determine whether the devices are being used to capture
content, regardless of whether such use is authorized by the department?
What policies govern local law enforcement agencies’ deployment and use of IMSI
catchers? To what extent do agencies comply with those policies?
Must local law enforcements agencies’ use of IMSI catchers always be subject to a
warrant issued by a judge? Do warrants specifically allow for the collection of data from
every cell phone that transmits to the devices?
To get answers to some of the above questions, SB 741 would require that a law enforcement
agency that acquires or uses an IMSI catcher must disclose a modest amount of information
about the policies that govern how the agency will use the device and the data gathered by the
device. SB 741 doesn’t prohibit any law enforcement agency from obtaining or using IMSI
catchers. The bill simply allows members of the public and their elected representatives to make
informed decisions about law enforcement’s deployment of surveillance technology in their
communities.
2. Local control. County sheriffs are elected officials. Because they are directly accountable to
the public, they should be allowed to make independent decisions about procuring and deploying
law enforcement technology to reflect local needs and priorities. State-imposed restrictions on
certain types of technology undermine a sheriff’s ability to use his or her discretion to enforce
the law and maintain public safety. By making it more difficult for sheriffs to use IMSI catchers,
SB 741 may compel them to use alternative technologies that may be less effective and result in
higher investigative costs. Those decisions may be more appropriately left up to sheriffs and the
voters who elect them.
3. Not far enough. Some civil liberties advocates suggest that SB 741 may not go far enough.
They suggest that SB 741’s public disclosure requirements, which allow the public to consider
and comment upon local IMSI policies, are an insufficient response to this problematic
surveillance technology. Instead, they want legislators to consider statewide standards that will
address some of the broader privacy and unreasonable search issues raised by IMSI catchers.
4. Double-referred. The Senate Rules Committee has ordered a double-referral of SB 741 --first to the Senate Governance & Finance Committee which has policy jurisdiction over state
laws relating to local governments, and then to the Senate Judiciary Committee.
Support and Opposition (4/9/15)
Support: Bay Area Civil Liberties Coalition; California Newspaper Publishers Association;
Small Business California.

Opposition: Citizens for Criminal Justice Reform - California.

-- END --