Across the country, police departments are increasingly intercepting and recording the private conversations of innocent people.

They're doing it with technological tools that surveil suspects and protesters, but also unsuspecting bystanders whose calls and text messages are vacuumed up by so-called "Stingrays," which operate as fake cell towers in order to hijack phone calls, text messages, and data streams.

The Federal Communications Commission needs to act swiftly to curtail the growing use of this invasive technology that's a clear and present danger to Americans' basic privacy rights. With the incoming Trump administration indicating it may gut the FCC, there is precious little time for Chairman Tom Wheeler to shine a light on the often highly secretive police tactic.

These fake cell sites aren't just surveilling individual targets, either. They interfere with everyday users, draining the batteries of cellphones and frequently degrading or entirely disrupting phone service, including 911 calls. And the FBI and local police departments have misled the public about when, where, and on whom these devices are used; and activists, lawmakers, and judges have all called for more transparency and oversight to determine the extent (and legality) of Stingray use.

What's certain is that Stingrays disrupt innocent civilians' communications – a practice that runs afoul of existing law. We know that Stingrays cause interference – from dropping and misrouting calls and interrupting 911 service. What's more, there's the potential for police to listen in on conversations legally protected by attorney-client, priest-penitent, and doctor-client privilege.

Local grassroots organizations and a dozen US senators have urged additional oversight of Stingrays and the enforcement of existing laws to protect civilians from harmful interference and illegal wiretapping.

Revelations of widespread spying on cellphone communications of entire communities by the FBI and local police (for example, Baltimore police surveilled the communications of potentially tens of thousands of residents) necessitates intervention by the FCC. It needs to rein in a practice that completely undermines decades of "presumption of privacy" precedence in our telephone conversations. That's why warrants are required prior to surveilling land line phones. This long-standing precedent needs to be clarified to apply to cellphones.

The extent and frequency of Stingray use has been hidden, too, in large part because Stingray maker Harris Corporation insists that local police sign a Nondisclosure Agreement (NDA). Government prosecutors have even dropped cases once it became apparent they would have to explain the (often warrantless) use of Stingrays to collect evidence against defendants. And judges, including in Baltimore, have thrown out evidence gathered by warrantless Stingray use, declaring that this use runs afoul of the explicit protections granted by our Bill of Rights.

For the past half-decade, the FBI has insisted the FCC requires local police departments to sign NDAs before Harris Corporation could sell them a Stingray – a mandate the FCC never made. In 2014, the FCC explicitly and publicly denied requiring police sign NDAs. And even more strangely, in 2015, the FBI stated that the NDA actually did not prevent prosecutors from disclosing Stingray use, contradicting their previously stance (and the language) of the NDA itself.

Stingrays aren't the only surveillance technologies that Baltimore Police have mislead the public about. In October 2016, the American Civil Liberties Union revealed the Baltimore Police Department lied in public statements when they stated they only kept aerial surveillance from their Cessna “spy plane” for 45 days. As it turned out, the Baltimore police have been keeping the data indefinitely, permanently tracking the movements of the population of Baltimore for unknown purposes.

Additionally, it appears that police in Baltimore and elsewhere are disproportionately targeting black communities with surveillance technologies. And that's especially troubling in cities with histories of racial discrimination.

The FCC has a responsibility to address the growing problem of discrimination in surveillance practices, protect innocent civilians from unwarranted surveillance, and enforce existing rules that prevent harmful interference to communications infrastructure. As numerous findings and filings document, our civil liberties are being violated and our right to privacy abrogated by practices that run afoul of existing FCC rules.

Chairman Wheeler owes it to the American people to enforce the law before the clock runs out.

Sascha Meinrath is the Palmer Chair in Telecommunications at Penn State and director of X-Lab, an innovative think tank focusing on the intersection of vanguard technologies and public policy. Follow him on Twitter @saschameinrath.

Jeff Landale is the executive assistant at X-Lab, a venture focusing on tech policy interventions. Follow Jeff on Twitter @JeffLandale.