What policies or biometric failures lead to ICE detaining citizens instead of noncitizens?

1. Policy shifts powering broader sweeps — “Arrest, even at court doors”

Several lawsuits and advocacy groups say DHS and ICE directives in 2025 encouraged more aggressive, targeted enforcement that included arrests at immigration courts and other nontraditional sites, increasing the chance citizens will be swept up alongside intended noncitizen targets; advocates sued to stop courthouse arrests after plaintiffs who appeared for hearings were detained ^{[4] [7]}. Congressional letters from lawmakers also demanded investigations, arguing ICE’s policies have made citizen detentions more frequent and that agency recordkeeping and field guidance remain opaque ^{[8] [9]}.

2. Expanded enforcement volume and capacity strain — “More people, more mistakes”

ICE and related reporting document a massive increase in enforcement activity in 2025 — hundreds of thousands of arrests across agencies and tens of thousands processed into detention during intense periods like the government shutdown — and ICE’s detained population hit record highs (roughly 60–66k), creating backlogs and pressure on screening systems that can exacerbate errors in determining citizenship ^{[3] [2] [1]}. Multiple outlets and legal advocates say overcrowded facilities and rushed operations raise the risk that agents will rely on imperfect or incomplete checks that miss or ignore proof of U.S. citizenship ^{[7] [1]}.

3. Biometric tools and “Mobile Fortify” — “When the app says ‘alien’”

Reporting and advocacy documents show ICE/CBP rolled out or used mobile biometric apps (commonly referenced as Mobile Fortify) allowing officers to scan faces in the field and treat a biometric match as highly determinative; senators and civil-rights groups warned that an apparent biometric match has been treated as definitive, and officers might ignore birth certificates or other documents if the tool indicates noncitizen status ^{[5] [6] [10]}. Lawmakers and watchdogs cited documented wrongful detentions tied to incorrect biometric confirmations and called for halting or auditing the technology ^{[6] [11]}.

4. Database unreliability and downstream errors — “Garbage in, garbage out”

Longstanding problems with DHS and national databases feed wrongful detentions. A federal court has previously found ICE’s own databases unreliable for probable-cause warrants, and critics say NCIC and other records contain inaccuracies that can produce false matches or outdated status flags — mistakes that field agents may treat as grounds to detain someone ^[5]. Internal documents and reporting also suggest agencies may keep nonmatch photos and biometric records for years, entrenching errors if misapplied ^[12].

5. Field practice and deference to technology — “Officers may prioritize a scan over documents”

Multiple sources show a tendency among some ICE actors to prioritize quick biometric confirmation or database indicators over on-the-spot documentary proof of citizenship; senators reported agents saying an app’s match can be treated as definitive, and advocates have documented incidents where citizens presented passports or birth certificates but were nonetheless detained or ignored ^{[6] [10] [1]}. The FBI and others have also warned about impersonation and the opaque use of unmarked officers, which complicates accountability and increases the chance of wrongful stops ^[13].

6. Competing official narrative and agency denials — “DHS: we don’t detain citizens”

DHS publicly disputed some reporting and insisted ICE does not arrest or deport U.S. citizens, saying enforcement is targeted and officers are trained to determine status; the department contends due diligence is built into operations ^[14]. That position conflicts with investigative tallies, legal claims, and advocacy documentation of citizen detentions, prompting Congressional calls for oversight ^{[8] [14]}.

7. Remedies, limits of available reporting, and accountability gaps — “Fixes are piecemeal”

Available reporting documents lawsuits, Congressional inquiries, calls to suspend biometric tools, and recommendations for better recordkeeping and courtroom protections, but it is not yet clear from the reviewed sources whether comprehensive policy changes or audits have been implemented systemwide; ICE’s published detention standards remain in place even as critics say practice diverges from policy ^{[15] [16] [11]}. Sources do not mention a complete, agencywide fix that eliminates the specific mix of policy choices and technical failures that produce citizen detentions.

Bottom line: the evidence in current reporting ties citizen detentions to both explicit enforcement choices (expanded sweeps, courthouse arrests, and tightened detention rules) and to technological and data failures (false biometric matches, unreliable databases, and field reliance on apps). DHS/ICE statements deny systemic detention of citizens, while journalists, advocates, and some lawmakers document dozens to hundreds of concerning incidents and demand investigations ^{[1] [8] [6]}. Available sources do not mention a definitive, agency-wide corrective action that has resolved these failure modes ^{[9] [5]}.