United States v. Cox, 684 F. App'x 706

Karen Cox was indicted for conspiracy to distribute ≥50 grams of methamphetamine (conspiracy period alleged: July 1, 2014–Sept. 24, 2015).
At trial the government presented extensive evidence from the charged conspiracy period and testimony about Cox’s methamphetamine purchases from January–March 2014 (predating the indictment period).
Cox objected at trial under Fed. R. Evid. 404(b) that the earlier sales were improper "other-act" evidence; she conceded they might fit a common-plan 404(b)(2) exception but requested a Rule 105 limiting instruction.
The district court ruled the pre-period sales were intrinsic ("inextricably intertwined") to the charged conspiracy, so Rule 404(b) did not apply, and denied the limiting instruction request.
Cox was convicted and sentenced to 121 months’ imprisonment and 60 months’ supervised release; on appeal she argued the pre-period evidence should have been excluded under Rule 403 as cumulative, unnecessary, and unfairly prejudicial.
The Tenth Circuit affirmed, concluding the evidence was probative of a continuous conspiracy and rebutted Cox’s single-supplier defense; it was not unfairly prejudicial or needlessly cumulative.

Issue	Cox's Argument	Government's Argument	Held
Admission of pre-conspiracy meth sales	Testimony about Jan–Mar 2014 sales was improper extrinsic bad-act evidence and should be excluded (404(b)); alternatively excluded under Rule 403 as unfairly prejudicial and cumulative	The sales were intrinsic/inextricably intertwined with the charged conspiracy and probative of continuity and multiple suppliers; not unfairly prejudicial or needlessly cumulative	Affirmed: evidence admissible; probative value outweighed any unfair prejudice
Need for limiting instruction (Rule 105)	Requested limiting instruction if evidence admitted under common plan/design exception	Court found Rule 105 unnecessary because evidence was intrinsic, not 404(b) other-act evidence	Denied: limiting instruction not required because evidence deemed intrinsic
Preservation of Rule 403 argument on appeal	Argued on appeal that district court should have excluded evidence under Rule 403	Government noted Cox primarily litigated Rule 404(b) below and may not have preserved Rule 403 for appeal	Court assumed preservation for review but rejected the Rule 403 argument on the merits
Standard of review for evidentiary rulings	N/A (procedural)	District court’s evidentiary rulings reviewed for abuse of discretion	Applied abuse-of-discretion standard; admission fell within permissible choice

United States v. Batton, 602 F.3d 1191 (10th Cir. 2010) (standard for abuse-of-discretion review of evidentiary rulings)
United States v. Stiger, 413 F.3d 1185 (10th Cir. 2005) (abuse-of-discretion standard explanation)
United States v. Mares, 441 F.3d 1152 (10th Cir. 2006) (permissible range of district court choices reviewed for abuse of discretion)
United States v. Shumway, 112 F.3d 1413 (10th Cir. 1997) (abuse-of-discretion framework)
United States v. Watson, 766 F.3d 1219 (10th Cir. 2014) (preference for admitting relevant evidence absent other proscription)
United States v. Irving, 665 F.3d 1184 (10th Cir. 2011) (same; evidentiary admission principles)
United States v. Rodriguez, 192 F.3d 946 (10th Cir. 1999) (Rule 403 exclusion is an extraordinary remedy to be used sparingly)
United States v. Smith, 534 F.3d 1211 (10th Cir. 2008) (Rule 403 protects only against unfair prejudice)
Deters v. Equifax Credit Info. Servs., 202 F.3d 1262 (10th Cir. 2000) (definition/discussion of unfair prejudice under Rule 403)