# Reverse Search Warrants **Domain:** Austin Research / Surveillance **Doc Type:** Operational mechanism **Source basis:** Supplied essay and the specifically identified records; verification scope is recorded in [[wiki/Austin Surveillance Evidence Ledger|the evidence ledger]]. **Reverse search warrants** begin with a criterion and seek unknown people whose records match it. A geofence uses a place and time; a reverse keyword request uses specified search terms or addresses. The direction differs from a query beginning with an already identified person. [[research/The Austin Surveillance Field|The Austin Surveillance Field]] places both techniques in the March 2018 Austin bombing investigation. It cites legal scholarship discussing location requests and March 14 keyword warrants directed to Google, Bing, and Yahoo, including Austin Division identifiers **18-MJ-168, 18-MJ-170, and 18-MJ-171**. The returned datasets and some case materials are described as sealed. The primary applications and returns were not obtained in this integration; the specific historical account remains attributed to the essay and its cited legal analyses. The architectural sequence is **criterion → matching traces → candidate identities → further investigation**. That sequence makes spatial and behavioral data useful before investigators know whom they are seeking. It also makes scope, false matches, minimization, and later identification separate operational questions. The comparison with [[wiki/Wastewater Surveillance|wastewater surveillance]] concerns starting from a signal and localizing its source. A sewer catchment yields collective biological information; a reverse warrant seeks accounts or people. Shared inference direction does not make the measurements, legal authorities, or identification resolution interchangeable. ## Connected entries [[wiki/Computational Addressability|Computational Addressability]] · [[wiki/Population State Estimation|Population State Estimation]] · [[wiki/Wastewater Surveillance|Wastewater Surveillance]] · [[wiki/Google Flu Trends|Google Flu Trends]] · [[wiki/Surveillance|Surveillance]] · [[wiki/Austin Surveillance Evidence Ledger|Austin Surveillance Evidence Ledger]] ## Sources and corpus context - [[research/The Austin Surveillance Field|The Austin Surveillance Field]] - [Mass Data Search Warrants and the Constitution — legal analysis cited by the essay](https://scholarship.law.upenn.edu/cgi/viewcontent.cgi?article=1903&context=jcl) - [Moderating Reverse Internet Keyword Warrants — legal analysis cited by the essay](https://scholarlycommons.law.northwestern.edu/cgi/viewcontent.cgi?article=1631&context=nulr) **Cluster:** [[wiki/Austin Surveillance Field|Austin Surveillance Field]] · [[wiki/Austin Executable Loop|Austin Executable Loop]] · [[wiki/Austin Surveillance Evidence Ledger|Austin Surveillance Evidence Ledger]]