What is relevant and prejudicial evidence in a criminal case?

A trial court must limit the introduction of evidence and argument to relevant and material matters. ( 1044.) Relevant evidence is that which tends in reason to prove or disprove a disputed fact of consequence. (Evid. Code, 210; People v. Merriman (2014) 60 Cal.4th 1, 78.) "[E]vidence of gang

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membership is often relevant to, and admissible regarding, the charged offense. Evidence of the defendant's gang affiliationincluding evidence of the gang's territory, membership, signs, symbols, beliefs and practices, criminal enterprises, rivalries, and the likecan help prove identity, motive, modus operandi, specific intent, means of applying force or fear, or other issues pertinent to guilt of the charged crime." (People v. Hernandez (2004) 33 Cal.4th 1040, 1049.)

Nevertheless, relevant evidence should be excluded if the trial court, in its discretion, determines that its probative value is substantially outweighed by the probability that its admission will create a substantial danger of undue prejudice. (Evid. Code, 352.) In this context, unduly prejudicial evidence is evidence that would cause the jury to "prejudge" a person on the basis of extraneous factors. (People v. Zapien (1993) 4 Cal.4th 929, 958.)