What is the most common probable cause that ICE officers use to detain someone.
Executive summary
The most common probable cause ICE cites to detain someone is that the person is "subject to removal"—frequently grounded in criminal convictions or immigration-related final orders—but in practice that official rationale increasingly rests on administrative records, database "hits," and encounters that begin with traffic or local-law enforcement stops rather than new judicial warrants [1] [2] [3]. Legal limits and court challenges persist, and recent data show a sharp rise in detentions of people without criminal convictions, revealing a gap between ICE’s stated detainer rationale and how detentions actually play out on the ground [4] [5] [2].
1. What ICE says it needs: probable cause that someone is removable
Statutory and internal ICE guidance require officers to establish probable cause that an individual is removable under federal immigration law before issuing a detainer or making a civil immigration arrest; ICE’s detainer policy explicitly links detainers to probable cause determinations, often tied to criminal convictions or public-safety concerns [1] [2]. The legal construct ICE invokes is administrative probable cause—an officer’s determination that the person falls into a removable category—which differs from a judicial warrant and does not always require a detached magistrate to sign off before the arrest [1] [6].
2. Criminal convictions remain the textbook trigger—officially
ICE formally emphasizes that detainers are "typically after a court has convicted [an individual] of one or more crimes" and that detainers are used especially where the person poses a public-safety or national-security threat, making prior criminal conviction one of the clearest bases for a probable-cause finding in ICE practice [2]. For categories of aliens tied to specified criminal or terrorism-related grounds, immigration law even mandates detention in many cases, reinforcing that criminal history is the canonical probable-cause pathway to custody [6].
3. Reality diverges: many detained people lack convictions
Despite that official framing, multiple reporting and data snapshots show the detained population has shifted: large proportions of people held in ICE custody have no criminal conviction, and detention growth since late 2025 has been driven overwhelmingly by people without criminal records, indicating ICE is relying on other forms of probable-cause or administrative grounds to arrest and detain [4] [7]. Investigations into the 2025 enforcement surge also link interior arrests to tactics—roving patrols, at-large arrests, and traffic stops—that draw in people without the classic conviction-based predicate ICE cites [8] [3].
4. How stops, database hits, and detainers function as practical probable cause
In many field encounters the sequence begins with routine traffic enforcement or local arrests that generate an interoperability hit or an ICE detainer request; ICE and local agencies then treat those administrative matches, prior removal orders, or database indicators as sufficient to assert probable cause that the person is removable, even when no new criminal charge exists [3] [2]. Civil-rights groups and courts have pushed back, arguing that reliance on detainers without timely neutral probable-cause review can amount to unlawful detention, a point underscored by litigation and consent decrees limiting warrantless ICE arrests [9] [10] [11].
5. Legal and policy tensions that shape what counts as "probable cause"
The distinction between administrative probable cause for immigration removal and the Fourth Amendment's criminal-arrest probable cause creates friction: courts have required prompt neutral probable-cause determinations in some circuits, and consent decrees and lawsuits continue to constrain ICE practices in several jurisdictions even as the agency asserts broad civil-enforcement authority [11] [10] [1]. Meanwhile ICE’s own public materials reiterate the statutory framework that centers removable status—often tied to criminal convictions or final orders—while outside reporting documents that many current detentions stem from administrative processes and traffic or local-law enforcement encounters rather than fresh judicial findings [2] [12] [3] [5].
Conclusion: the most common practical answer, and the caveat
Formally, the most common probable-cause ground ICE asserts is that an individual is removable—most straightforwardly demonstrated by a criminal conviction or final order of removal—but in practice ICE detention increasingly rests on administrative records, database hits, and initial traffic or local-law enforcement encounters that are treated as sufficient predicates; this divergence has produced legal challenges and a detained population with a substantial share of people who lack criminal convictions [2] [4] [3] [9]. Available reporting documents these patterns; it does not allow a precise, single-number accounting of which exact basis is used most often in every arrest, and local variations and litigation mean the answer can differ by jurisdiction [4] [10].