Denver mayor and staff used encryption app to discuss migrant crisis, then auto-deleted messages. Trump policies prompted move, says spokesperson
Denver Mayor Mike Johnston and 14 of his top advisors, appointees and lawyers nicknamed themselves "Strike Force" and communicated about the city's migrant crisis through an end-to end encryption app, CBS News Colorado has learned. The app, Signal, proceeded to automatically delete their initial conversations.
A spokesperson for Johnston said the Signal messaging was prompted by President Trump and how his administration "could have significant impacts on how Denver operates."
The use of such messaging apps by government officials has been controversial and viewed as a way to avoid public disclosure of government decision making. In Michigan, after state police leaders were found in 2021 to be using Signal on state-issued phones, state lawmakers outlawed the use of encrypted messaging on state phones.
"It's unlawful and it's breaking the law," said Steven Zansberg, a Denver attorney who specializes in First Amendment and open records law, and reviewed some of the records obtained by CBS News Colorado.
Jeff Roberts, director of the Colorado Freedom of Information Coalition, characterized what the CBS investigation found as an intentional effort to undermine Colorado's open records law.
"This is not transparent," said Roberts.
According to Johnston's daily calendar, obtained through an open records request, on Jan. 14, 2025, he convened a "Strike Force Introduction" meeting. The following day, Jan. 15, text messages obtained by CBS News Colorado via an Open Records request, show Johnston's Director of Strategic Initiatives, Joshua Posner, sent an identical text message to multiple members of the administration saying: "We are going to use Signal to communicate with Strike Force so that communication remains encrypted and secure(and messages auto delete)"
He sent the staff members a link to download Signal saying once that was done, "I can add you to the group."
Signal is a messaging app that encrypts communications and also automatically deletes messages after a specified amount of time ranging from 30 seconds to four weeks. The city has confirmed that Johnston's group was auto-deleting their initial internal messages. The mayor's spokesperson said the auto-deletion went from Jan. 15 to Jan. 24 when they then set it to retain the messages for four weeks. And then on Jan. 29 they disabled the deletion function entirely.
The mayor's spokesperson, Jordan Fuja, said the Strike Force Signal group is still in use when there are relevant updates that impact Denver.
She declined to make the mayor or anyone else available for an interview on the Signal messaging.
The Johnston administration's move to make their communications more difficult to access came about three weeks after America First Legal, a Trump-affiliated legal group, filed requests with Johnston and his administration seeking city records and communications related to immigration issues. Part of the request demanded, "All records, including communications, calendar entries, and documents mentioning or belonging to Mike Johnston, Mayor since November 1, 2024."
In a written statement, Fuja said the move to Signal was because, "When President Trump took office in January, it was clear that there would be rapidly developing changes to the way the federal government interacts with cities that could have significant impacts on how Denver operates. The particular group was started in January for internal staff to easily keep track of and share information regarding federal actions that impact Denver under the new administration."
Roberts said the internal text messages and move to Signal show "they are giving the impression that we are doing something we don't want the public to see. The city is saying at the get-go 'These are records the public should never see.'" He suggested the Johnston administration was intentionally "concealing, hiding."
Zansberg, who specializes in open records issues, said what was done was "unlawful and breaking the law and it deprives us of the rights we have as Coloradans to observe the conduct of public business."
He suggested the automatic deletion of the Strike Force conversations likely violated Denver's data retention policies.
"Typically three years is the standard records retention," said Zansberg.
The mayor's spokesperson disputed that, saying "The City retention schedule does not obligate city employees to retain electronic mail messages."
In another text conversation between Acting Denver City Attorney Katie McGloughlin and the mayor's Chief of Staff, Jenn Ridder, McGloughlin wrote, "Signal says you're in it I'll ask Josh to resend invite." Ridder responds, "Haven't heard anything." At another point, someone else texts the mayor's chief of staff, asking "are you on signal? Mind if we shift there?" Ridder responds, "Yes switch there."
Zansberg said, "It seems like a pretty plain, straightforward, deliberate effort to evade transparency."
After he was elected mayor, Johnston cited transparency as one of his five guiding principles.
The move to the encrypted messaging app also came a month after the mayor's office was specifically instructed by its own Information Security Chief not to use Signal.
In a Dec. 11, 2024, email from Denver Chief Information Security Officer Merlin Namuth shared with McGloughlin and several other mayoral staff members and appointees, Namuth discussed the use of encrypted messaging apps and said, in bold letters, they were "For personal use only. Please avoid using these applications for city work."
At least two of Johnston's appointees -- Police Chief Ron Thomas and Manager of Public Safety Armando Saldate -- were asked by the mayor's office to join Signal and be part of the Strike Force group. Both rebuffed the mayor's invitation and declined to join, according to the CBS News Colorado Investigation. Fuja claimed "The purpose of the group is solely for information sharing, not actionable directives, so there was no need for safety leaders to be a part of it."
Records show, though, that safety leader Sheriff Elias Diggins, along with Matt Mueller, Denver's emergency manager, and Wendy Shea, an attorney for the Department of Safety, were asked to join and did so.
Zansberg said what is now being revealed "is ultimately very toxic" and "creates greater distrust and a loss of confidence."
