Clinic Authors Amicus Brief for Judges on Protection for Immigration Detainees
Represented by Yale Law School’s Peter Gruber Rule of Law Clinic and Zuckerman Spaeder LLC, a bipartisan group of 135 former federal and state judges authors an amicus brief in Lopez Belloza v. Hyde, urging the 1st Circuit to apply the unknown custodian doctrine to stop Immigration and Customs Enforcement’s (ICE) practice of transferring detainees to undisclosed locations and then seeking dismissal of their habeas petitions on jurisdictional grounds. Under the doctrine, district courts would retain habeas jurisdiction over petitions filed on behalf of such detainees, so that ICE cannot erode their access to the Great Writ.
The 135 amici are former judges who served on federal or state courts. Federal amici were nominated to the bench by five different presidents, from both the Republican and Democratic parties. While on the bench, they spent decades safeguarding the Great Writ of habeas corpus—which the Constitution guarantees to limit unlawful executive detention, according to the clinic. State amici served in 22 different states and the District of Columbia and joined the brief to stand alongside their federal counterparts to protect the Writ’s critical role in upholding the rule of law.
The amici argue that the First Circuit should follow its precedent in Vasquez v. Reno and the Supreme Court in Rumsfeld v. Padilla by applying the unknown custodian doctrine; in such cases, counsel cannot identify a detainee’s immediate custodian because ICE has not disclosed their location. In such “extraordinary circumstances,” amici argue, detainees can name a higher-level official as respondent, with their last-known district of confinement retaining jurisdiction over their petition. Amici argue that this doctrine is necessary to ensure that ICE cannot extinguish habeas jurisdiction by using its custody to transfer detainees to undisclosed locations and then seek to dismiss or transfer their habeas petition on the ground that they were filed in the wrong court.
The facts of Lopez Belloza itself, amici argue, present a textbook case for the doctrine. Appellant Any Lucia Lopez Belloza was arrested by ICE at Boston Logan International Airport while heading home for a school vacation, transferred to Texas without notice to her counsel, and deported to Honduras — in violation of an emergency court order — all within 24 hours of her counsel filing a habeas petition in the District of Massachusetts, her last-known district of confinement, according to the brief. The court below dismissed her petition for lack of jurisdiction, concluding that the unknown custodian doctrine did not apply because ICE had not acted “furtively.” Amici argue that neither 1st Circuit nor Supreme Court precedent requires a showing of deliberate manipulation by the custodian. The doctrine applies whenever a detainee’s location is undisclosed, whether by neglect or design.
As the brief explains, the unknown custodian doctrine has deep historical roots, traceable to Parliament’s rejection in 17th-century England of custodians’ “tricks” to use their custody of the prisoner to evade habeas jurisdiction — including by rushing prisoners from one facility to another just ahead of the writ. The brief traces how courts in this country have carried forward that tradition by recognizing that the writ must be “administered with initiative and flexibility” to ensure that “miscarriages of justice within its reach are surfaced and corrected.”
Application of the unknown custodian doctrine is particularly necessary because this case, amici argue, is part of a broader, nationwide ICE practice. Since January 2025, ICE has abruptly detained immigrants, rapidly transferred them across jurisdictions without notifying their counsel, and then moved to dismiss the habeas petitions on jurisdictional grounds. Left unsupervised by the courts, amici argue, this pattern, reduces the Great Writ to “a game of jurisdictional hide-and-seek.” In response, courts across the country have adopted standing orders limiting ICE’s ability to evade habeas review. Amici describe these measures as necessary to maintain jurisdiction and “preserve the fabric of habeas,” which is “essential both to protect individual liberty and to prevent executive evasion of mandatory judicial oversight.”
“We hope that the breadth of experience and variety of backgrounds our amici bring drives home the importance of this case for the 1st Circuit,” explained Kaitlyn Van Baalen ’27, the student team leader on the brief. “ICE nondisclosure and noncompliance are becoming tragically common. The time is ripe for the court to apply the unknown custodian doctrine to help district courts navigate these unprecedented challenges.”
“When ICE transfers immigrant detainees to undisclosed locations and evades habeas corpus review, it doesn’t just harm one person — it erodes the constitutional foundation that protects us all,” added Trinh Q. Truong ‘27, another student team leader on the brief. “The unknown custodian doctrine is necessary to ensure that procedural gaps cannot swallow the Great Writ.”
Amici are represented by the Peter Gruber Rule of Law Clinic at Yale Law School and cooperating attorney Aaron Zelinsky ’10 of Zuckerman Spaeder LLC. Founded in 2016, the Peter Gruber Rule of Law Clinic addresses threats to the rule of law in the United States and around the world. The clinic was founded by Sterling Professor of International Law and former Dean Harold Hongju Koh and William O. Douglas Clinical Professor of Law Michael Wishnie ’93. The Clinic is now led by Koh, Aharon Barak Distinguished Rule of Law Fellow Bruce C. Swartz ’79, Peter Gruber Rule of Law Fellow Sonia Mittal ’13, and Cooperating Attorney Mary Hahn ’01, as well as Visiting Lecturers in Law Eugene Fidell, Margaret Donovan, and Justin Cole ’23.
Current Yale Law students and clinic members who worked on the brief include Kaitlyn Van Baalen ’27, Trinh Q. Truong ’27, Riler Holcombe ’26, Cameron Cucuzzella ’27, John David Cobb ’28, Alyssa Penick ’28 and Ava Sharifi ’28.
