United States v. Ozuna, 2012 U.S. App. LEXIS 5666

Ozuna was convicted of unlawful possession of a firearm by a felon under 18 U.S.C. § 922(g)(1) and sentenced to 113 months.
Sanchez testified at trial about events of November 7, 2009 and claimed sole possession of the gun.
The government sought to introduce gang-evidence linking Ozuna and Sanchez; the district court limited the gang references and reserved final admissibility.
Sanchez admitted a past gang affiliation; the government cross-examined him on gang rules and loyalty.
The district court gave a cautionary jury instruction that gang membership could not prove guilt, and Ozuna was ultimately found guilty.
Ozuna moved for a new trial under Rule 33, alleging improper admission of gang-evidence; the district court denied relief.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether admission of gang-evidence was an abuse of discretion	Ozuna: evidence prejudicial under Rule 403.	Ozuna: door opened by Sanchez; gang evidence should be excluded.	No abuse; evidence probative of bias and motive.
Whether the error was harmless given the trial record	Government: evidence enhanced credibility of Sanchez.	Prejudicial risk outweighed probative value.	Not an abuse; probative value outweighed prejudice.

United States v. Santiago, 643 F.3d 1007 (7th Cir.2011) (admission reviewed under abuse-of-discretion framework for Rule 403)
United States v. Harris, 587 F.3d 861 (7th Cir.2009) (prejudicial risk of gang evidence acknowledged but admissible if probative)
United States v. Montgomery, 390 F.3d 1013 (7th Cir.2004) (gang evidence admissible where probative of bias/motive)
United States v. King, 627 F.3d 641 (7th Cir.2010) (relevant analysis of gang membership and bias)
Clark v. O'Leary, 852 F.2d 999 (7th Cir.1988) (general principle on probative value of organizational affiliation)
United States v. Abel, 469 U.S. 45 (1984) (bias as a probative factor; organization membership can indicate bias)