United States v. Lilly, 810 F.3d 1205

DEA arrested Janet Lilly’s fiancé with meth; DCI agents interviewed Lilly and obtained incriminating statements and recruited her as a confidential informant.
DCI agents suggested cooperation would “help” and might reduce consequences; Lilly later signed a CI agreement; no written federal non-prosecution agreement or formal involvement of the U.S. Attorney’s Office.
Lilly provided controlled buys and assistance for months but was later indicted in federal court for conspiracy to distribute methamphetamine (indictment covered Jan 2010–Apr 2013).
Lilly moved to enforce an alleged agreement that the United States would not prosecute her for conduct through Nov 21, 2011; the district court denied the motion for lack of authority by DCI/DEA to bind the United States.
Lilly entered a conditional guilty plea, reserved appeal of the denial, was sentenced, and appealed the district court’s ruling that no federal immunity promise was enforceable against the United States.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether an alleged promise by DCI/DEA not to prosecute binds the United States	Lilly: DCI/DEA promised federal non-prosecution and proffered statements would not be used	Government: Neither DCI (state) nor DEA (federal investigators) had actual authority to bind the U.S.; no U.S. Attorney participation	Court: No — promises unenforceable absent actual authority to bind the United States
Whether state agents (DCI) can bind federal prosecution	Lilly: DCI acted for/with DEA thus bound U.S.	Government: State officials lack power to bind sovereign federal prosecutorial discretion	Court: No — state agents cannot bind the federal government
Whether DEA had implied or express authority to grant immunity	Lilly: DEA involvement makes promise federal	Government: No statute/regulation or necessary implication grants DEA power to promise immunity; investigatory power ≠ power to grant immunity	Court: No — neither express nor implied actual authority shown for DEA to bind U.S.
Whether a fundamental-fairness exception or supervisory power requires enforcement	Lilly: Enforcement is required by fairness; she relied and incurred risk	Government: Merrill rule controls; fairness exception is narrow and not met; prosecutors didn’t authorize promises	Court: No — case is a typical investigator-promise situation, not the extraordinary circumstances needed to invoke a fairness or supervisory remedy

Fed. Crop Ins. Corp. v. Merrill, 332 U.S. 380 (1947) (government not bound by agent actions beyond actual authority)
Office of Personnel Management v. Richmond, 496 U.S. 414 (1990) (discussing Merrill as leading estoppel precedent)
United States v. Flemmi, 225 F.3d 78 (1st Cir. 2000) (investigators’ promises unenforceable absent actual authority; narrow fairness exception discussed)
United States v. Ellis, 527 F.3d 203 (1st Cir. 2008) (party must show actual authority to bind government)
Dresser Industries, Inc. v. United States, 596 F.2d 1231 (5th Cir. 1979) (risk of unauthorized promises and need for actual authority)
United States v. Cooper, 70 F.3d 563 (10th Cir. 1995) (breach-of-plea context enforces promises made by authorized prosecutors)
Santobello v. New York, 404 U.S. 257 (1971) (prosecutorial promises as part of plea bargains must be honored when made by authorized prosecutors)
United States v. Kettering, 861 F.2d 675 (11th Cir. 1988) (DEA lacks authority to bind U.S. on plea terms absent prosecutor authorization)