HSI Undercover Agents Join a Live Whipple Watch Signal Call: Reports From the 'Stalking of ICE Employees' Case Reach the US v. Sant Docket

On May 22, 2026, Homeland Security Investigations undercover agents, designated UCA-SC-003 and UCA 7810, were “participants in some of the group chats” of the Whipple Watch observer network and joined a live Signal group call run over the network’s chat about the Bishop Henry Whipple Federal Building at Fort Snelling, Minnesota, according to HSI’s own report of investigation. The report, ROI MS05FR26MS0009-015, is in HSI case MS05FR26MS0009, opened 4/20/2026 under the title “Stalking of ICE Employees by Rapid Response Network Members.” It reached the public record as Exhibit K to Doc. 297, which defendant Isaac Auman Sant filed in United States v. Sant, 0:26-cr-00115 (D. Minn.). Exhibit O, ROI MS05FR26MS0009-020, was filed with it.

What the first report records

• Authorship. The narrative “was written by SA J. Johnson and uploaded into ICM by SA M. Siffermann”; Matthew Siffermann is the reporting agent and Supervisory Special Agent Hakan Catalan approved it on 5/28/2026 (approval date).
• The call. The report says the live call ran “approximately 11:00 a.m., through 1:30 p.m.” and lists its participants by role with physical descriptions. Those participants are private individuals and are not reproduced here.
• Vehicles. A list headed “vehicles being used to follow suspected ICE Agents” gives make, model and year with registered-owner lookups. The ROI names defendants in the case among the owners, Natasha Lee Rakotz and Isaac Auman Sant, each marked “CONFIRMED COMMUTER.” The heading is HSI’s characterization. Owners who are not defendants are not named here.
• The Wisconsin BOLO. The agents’ notes say a caller on the call “advises Dispatch they are approaching the state line to Wisconsin” and asked for a BOLO to Wisconsin. The agents add that he “confirmed with dispatch at least twice to pass the information over to unknown subjects in Wisconsin.” This is the agents’ account of a call they were on; the filed copy has no recording or transcript.

What the second report records

ROI MS05FR26MS0009-020 was approved on 6/10/2026 (approval date) by Timothy Hatton, whose title on the approval line is “SPECIAL AGENT,” not a supervisory title. Its synopsis says Rakotz “stalked and harassed an HSI St. Paul employee” on May 13, 2026. That is HSI’s characterization in its own report, not a finding. The narrative is by HSI St. Paul Assistant Special Agent in Charge Tonya Price, who is the employee in the encounter: she says a car followed her from the Whipple building across a bridge into Dakota County, and that the driver began “demanding to know” “who my boss is.” Price says she recognized the driver on May 22, 2026, when Siffermann emailed her photos.

Why it matters

These reports are primary documents showing what HSI’s undercover infiltration of rapid-response groups looked like on the ground: agents inside an observers’ Signal channel during an operation, logging who was on the call and which vehicles were being watched, with registered-owner lookups already run. The corpus’s earlier source on this case is only a one-line summary in the FOIA-released HSI St. Paul consolidated report (2026-07-23–hsi-st-paul-consolidated-report-puppet-box-cooperation-cannon-river-rapid-response-network-undercover-agents).

See also: the indictment entry 2026-06-16–minnesota-us-attorney-indicts-15-direct-action-minnesota-antifa-ties and the wider infiltration record 2026-08-13–operation-puppet-master-hsi-infiltrates-minnesota-anti-ice-community.

Not established

• Who else was on the call, and what the observers’ own purpose was; the ROI describes only what the agents wrote down.
• How the photos Siffermann emailed on May 22 were obtained, and whether they connect to the call; neither report says.
• Whether the Wisconsin BOLO was placed or acted on.
• How the registered-owner lookups were run, under what authority, and when relative to the call.
• Why Sant’s counsel put these reports before the court: the docket text for the exhibit reads only that it responds to a pending motion. Both PDFs on CourtListener are image-only scans; the quotes above were read from page images.