The Milwaukee Police Administration Building downtown. (Photo | Isiah Holmes)
The Milwaukee Police Department (MPD) has purchased new cell phone surveillance technologies in recent years and has acquired upgrades for others. Such equipment changes generally don’t garner much notice from the public or local elected officials. But they have raised alarm bells for privacy advocates, who fear that transparency and oversight of police-initiated surveillance is far behind the technologies themselves.
Contracts obtained by Wisconsin Examiner show at least two technologies are used to track and intercept phones in Milwaukee. One is a Cell Site Simulator (CSS), which tricks nearby phones into connecting to it by mimicking a cell tower. The devices are more popularly known as Stingrays after a particular brand produced by the Harris Corporation. Other companies have stepped in to fill a void left after Harris moved away from providing Stingrays to local police.
Two ways to track and intercept a phone
In 2019, the MPD purchased a new cell site simulator from the North Carolina-based company Tactical Support Equipment. In its contract with the department, the company describes itself as a veteran-owned small business. Its device was purchased using a $498,900 grant, according to a commodity contract obtained by Wisconsin Examiner. Later that same year, the MPD purchased a C-Hostile Emitter Angle Tracker (C-HEATR) using a federal grant for $36,632. The C-HEATR acts as a remote handheld mapping device that works in unison with the cell site simulator. Basically, the main device tracks a phone to a general area and then officers use the handheld C-HEATR to get more precise location data.
In 2022, the MPD upgraded its cell site simulator system. First an upgrade was purchased in July which added four channels to the system and gave it the ability to track 5G phone signals at a cost of $328,700. Mike Katz-Lacabe, director at the Center for Human Rights and Privacy, told Wisconsin Examiner that the more channels a cell site simulator can access, the more service providers, like AT&T, Verizon or Tmobile, it can mimic. When it was first acquired in 2019, the new cell site simulator system had eight channels. The upgrade brought the number of channels up to 12. Later the same year the department purchased a 12-channel portable base station with full 5G coverage for $951,750. Insurance for the cell site simulator also more than doubled to $5 million.
The contract notes include costs for training for six people. Just one of those individuals, Officer Christopher Randazzo, has been identified by MPD. Since early 2022, the Special Investigations Division — which focuses on drugs, guns, gangs, and fugitive apprehension — has maintained the cell site simulator system. The SID, however, also uses another piece of cell phone surveillance technology, though one which has not been publicly linked to MPD before.
PenLink is a Nebraska-based company which produces technologies to help police intercept and analyze phone or social media data. In February 2022, Forbes reported on a recording that had discreetly captured PenLink representatives boasting of their product’s ability to intercept social media. The rep said that near-live tracking of suspects can occur free of charge, but that social media intercepts are often not as real-time as phone taps. Using Facebook to track someone involves a 15 minute delay, for example.
Although contracts for MPD’s Penlink date to 2019, parts of the documents mention amendments dating to 2017. A spokesperson for the department was unable to determine exactly how long MPD had used the service. Maintenance for the Penlink software was purchased for $6,580, increasing the contract’s total from $12,672 to $19,008. The contract also included two different kinds of software to intercept phones and telephones. An MPD spokesperson told Wisconsin Examiner, “We use it for live intercepts and to analyze call records and social media records.” Yet, when asked about whether PenLink is used to intercept social media, the department pushed back. “This state doesn’t allow us to intercept social media,” the spokesperson said. “Penlink is able to collect phone data for Pen Register and Trap and Trace Intercepts. It’s also used in [Title 3] investigations to intercept live content.”
The spokesperson added that PenLink has no operational relationship with the cell site simulator, despite their similar usage. Records show that aspects of the contract for the new cell site simulator system and agreements for the Penlink software were both finalized in May of 2019.
MPD’s statement that it cannot intercept social media in the state echoes arguments made by Republican lawmakers who pushed to re-define what pen registers are in Wisconsin. Legislators claimed that getting a pen register-equivalent for social media is difficult for law enforcement in the state. Pen registers are a kind of intercept which collects the numbers calling to or being called by a particular phone.
Open records requests released on the website Muckrock suggest that in the past, MPD has used affidavits for pen registers or trap and trace devices — essentially the same thing — to get approval to use cell site simulators. This scenario is precisely what telecommunications experts began to warn of when the GOP-backed legislation was being floated around the Capitol.
Tim Muth, staff attorney at the American Civil Liberties Union (ACLU) of Wisconsin, stressed that the bill was problematic. “The proposed legislation broadens the surveillance powers of state and local law enforcement, allowing the government to gather a broad swath of ‘metadata’ about our phones and electronic communications,” Muth told Wisconsin Examiner. “Existing law authorizes court orders to install ‘pen registers’ and ‘trap and trace’ devices solely for the purpose of recording the phone numbers for incoming and outgoing calls received by a specific phone.” The new law, however, would allow for “dialing, routing, addressing, or signaling information,” which could be read to mean senders and recipients of a target’s emails, instant messages, and chats, plus phone location data. As written, the current law does not allow for this level of surveillance, Muth explained.
Transparency and oversight is lacking
For many surveillance technologies used by police, it’s unclear what their full capabilities may be. Although cell site simulators can certainly track location, they can also be used to intercept content, disrupt cellular networks, and even send fake short messages. Whether any of these features have been used by local law enforcement, however, is unknown. MPD has, in the past, denied that it’s cell site simulator can intercept calls, messages, or other content. PenLink may be used for pen register investigations, and to intercept live content, but the MPD says it has no connection to the cell site simulator, which can also serve some of those roles. And while PenLink is used to intercept social media by police elsewhere in the country, MPD says they’re not allowed to in Wisconsin.
Privacy advocates argue that the police lack rigorous oversight. “In order for local government to make informed decisions about the technology used by its police department, it’s important that they be informed not only about the purchase of the technology, but also how it works and what it will be used for,” Katz-Lacabe told Wisconsin Examiner. “The police should be accountable to the local elected officials and the elected officials need to be accountable to the public. In too many cases, police departments have acquired surveillance technology without the knowledge of the local elected officials. In Oakland, the police purchased a cell site simulator in 2006, but local elected officials didn’t know about it until 2013.”
Three years later in 2016, the city of Oakland, California, established a privacy advisory commission which served as a local oversight body for surveillance technology. Muth agrees that local oversight of surveillance in Milwaukee is lacking, and needed. The ACLU of Wisconsin supports the adoption of Community Control Over Policing Surveillance (CCOPS) ordinances. These would require police departments to get community buy-in before acquiring new surveillance technologies. It also sets up a transparent process so that the public can see clearly what’s going on.
This system needs to be brought into the light of day so that the residents of Milwaukee can understand, debate, and put limits on the systems which are surveilling them without their knowledge or consent.
– Tim Muth, senior staff attorney, American Civil Liberties Union (ACLU) of Wisconsin
The ACLU of Wisconsin has detected malpractice with cell site simulators in the past. Back in 2016, it was revealed that police were using oddly vague language to hide their use of cell site simulators from courts. Like other police departments, the MPD referred to the technology as a “confidential source.” To this day, the MPD team that handles the cell site simulator is known as the “Confidential Source team.”
Muth says that “because of the lack of transparency by the Milwaukee Police Department, and frankly most law enforcement agencies in the state, it is difficult to say with certainty that such technologies have been used in illegal manners in the past. What we can say with certainty is that the Milwaukee Police Department and other agencies are rapidly expanding a system of surveillance, both online and in physical space, which creates serious concerns about privacy rights. This system needs to be brought into the light of day so that the residents of Milwaukee can understand, debate, and put limits on the systems which are surveilling them without their knowledge or consent.”
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