United States v. Morgan, 2015 U.S. App. LEXIS 8187

Defendant Morgan was tried on drug- and gun-related charges; prosecution relied heavily on witness Keysha Williams and a cooperating informant.
On direct, Williams testified that Morgan sent letters from jail asking her to arrange the murder of the government informant (e.g., "he ha[d] to die").
Defense objected under Rule 403 as highly prejudicial and unrelated to the charged offenses; the district court acknowledged the prejudice but denied a mistrial or striking the testimony and gave no limiting instruction.
The court initially excluded Morgan’s death-threat letters as cumulative, but after cross-examination introduced Williams’s bail letter (supporting Morgan), the government successfully reopened the door and the court permitted Williams to testify to Morgan’s threat-letters on redirect.
Morgan was convicted on all counts; he moved for a new trial arguing wrongful admission of the death-threat testimony and letter and improper prosecutorial argument inviting an adverse inference from those threats.
The Second Circuit vacated and remanded for a new trial, holding the district court abused its discretion in admitting the death-threat evidence and that the error was not harmless.

Issue	Prosecution's Argument	Morgan's Argument	Held
Admissibility of death-threat testimony on direct	Probative of consciousness of guilt and guilty knowledge	Highly prejudicial, unrelated to charged crimes; no important purpose under Rule 403	Abuse of discretion to admit: threats were unrelated to charged offenses and prejudicial effect outweighed probative value
Admission of defendant’s death-threat letters on redirect (open‑door)	Defense opened the door by introducing bail letter; letters show change in witness’s state of mind and are admissions by Morgan	Bail letter did not create a change in Williams’s state of mind relevant to Morgan; letters were cumulative and not opened	Government failed to show a proper basis; letters were admitted for improper purpose (to show bad character/danger), so admission was erroneous
Harmlessness of erroneous admission	Evidence of guilt was sufficient overall; any error was harmless	Death-threat evidence was "toxic" and likely swayed the jury; prejudicial and amplified by summation	Error not harmless: threats were dramatic, emphasized by government, and record does not assure jury was not substantially swayed

United States v. DeLillo, 620 F.2d 939 (2d Cir. 1980) (Rule 403 framework for death-threat evidence)
United States v. Qamar, 671 F.2d 732 (2d Cir. 1982) (death-threat evidence requires an important purpose)
United States v. Check, 582 F.2d 668 (2d Cir. 1978) (permitting death-threat evidence only when clearly needed; doctrine of opening the door)
United States v. Quinones, 511 F.3d 289 (2d Cir. 2007) (deference to district court but requires conscientious Rule 403 balancing)
Old Chief v. United States, 519 U.S. 172 (1997) (inadmissible evidence may lure jury to decide on improper emotional grounds)