Denver Mayor Mike Johnston and his top aides used an encryption app that auto-deleted messages used to communicate about the illegal immigration crisis plaguing his city —  a practice that First Amendment experts said violated the city’s own records retention policies and the state’s open meeting laws.  

CBS News Colorado reported that Johnston and 14 of his advisers, lawyers and appointees used the app Signal as part of a group within the administration called “Strike Force.”

CBS News Colorado quoted a mayoral spokesperson as saying Johnston’s use of the messaging app was prompted by President Donald Trump and how his administration “could have significant impacts on how Denver operates.”

The mayor’s office did not directly address several questions, including whether Johnston and his aides downloaded the text messaging app using government-provided cellphones, and, if the devices were issued by the city, whether the city’s IT department approved the download of the auto-deleting software.

A city spokesperson defended Johnston’s use of the app and insisted that it does not violate laws.

“Signal is a well known collaboration tool that creates an easy and convenient messaging platform, particularly for large groups. It is especially useful for people who use different operating systems (iPhone, Android) and allows users to efficiently connect with each other,” said Jordan Fuja, who speaks for the mayor’s office.  

Fuja said the “Strike Force” still exists and the mayor taps the group “when there are relevant updates that impact Denver.”

“The use of this platform has not violated any law or city retention policy, and all communications, regardless of the platform used, are subject to open records requests,” she said.  

Attorney Steven Zansberg, a First Amendment lawyer who has represented the interests of media companies in litigation, reviewed some of the records obtained by CBS News Colorado and concluded that Johnston and his aides violated Colorado laws.

“First, instantaneous destruction of telecommunication correspondence with members of the Strike Force outside the city government violates Schedule 145 of the City’s Records Retention policy,” Zansberg told The Denver Gazette. “Second, because the Strike Force is a formally constituted group of the City and County of Denver, any messages shared among three or more members of that ‘local public body’ constituted a ‘public meeting’ from which the public was unlawfully excluded.”

Jeff Roberts, director of the Colorado Freedom of Information Coalition, said the use of “ephemeral messaging apps” among public officials “undermines the purpose of  Colorado Open Records Act, which is to ensure access to the records of government so that the public can be informed and hold officials accountable.”

Roberts was referring to CORA, which requires that most public records be made available for public inspection. The law applies to “all writings made, maintained, or kept by the state, or any political subdivision thereof” used in the “exercise of functions required or authorized by law or administrative rule.” 

Zansberg additionally implicated the state’s open meetings law, which experts view as an antidote against secrecy. The law declares that the formation of public policy is “public business and may not be conducted in secret.”

CBS News Colorado had obtained records showing that on Jan. 14, Johnston convened a “Strike Force Introduction” meeting and on Jan. 15, Joshua Posner, the mayor’s director of strategic initiatives, sent this identical text message to multiple administration members: “We are going to use Signal to communicate with Strike Force so that communication remains encrypted and secure (and messages auto delete).”

Posner then sent a link to download Signal and told people he can “add you to the group,” the TV station reported. 

CBS News Colorado broke the story a few weeks after Republican members of the U.S. House Committee on Oversight and Government Reform threatened to refer Democratic mayors, such as Johnston, to the Department of Justice for criminal investigation.

At the center of the congressional hearing in March were the policies by municipalities dubbed “sanctuary cities” to prevent or discourage local law enforcement from reporting an individual’s immigration status to federal authorities.

Johnston’s use of encryption services occurred amid a debate at the state Capitol over what some described as the Democratic-controlled legislature’s attempts to make it difficult for the public and the media to access public records or figure out what policymakers are up to.

Notably, lawmakers passed a law last year that exempted the legislature from parts of the Open Meetings Law. This year, lawmakers are pushing Senate Bill 77, which seeks to extend deadlines for public records custodians to fulfill requests from three days to five and even longer in “extenuating circumstances,” which is not clearly defined.  

Lawmakers have maintained that the laws they’ve passed and measures they’ve proposed would make accessing public records more practicable for government custodians. They also argue that before they changed the open meetings law, it was unworkable.

The practice of using auto-deleting apps among elected leaders is not new.

In 2023, two House Democrats sued the Colorado House of Representatives and both Democrats and Republicans, alleging both parties, with support from leaders, regularly participated in meetings that violated the Colorado open meetings law and used encrypted messaging service Signal to discuss public business outside of public view, with the messages set for automatic deletion.

The lawsuit — which the House leaders settled — claimed that, as a result of using Signal, the digital communications among lawmakers were not available to the public for observation and because they were set for automatic deletion via the app’s self-destructing message function, they were not retained or available for public inspection under CORA.

Reporter Deborah Grigsby Smith and Editor Luige del Puerto contributed to this article.