The Pre-Trial Discovery Process Should Be Used To Avoid Surprises And Unsubstantiated Opinion From Being Presented To The Jury

Informal discovery requests must be made 15 calendar days before a formal motion to compel discovery is filed with the court.[1]  Motions to compel discovery should provide the information you wish and the authority for such discovery.

Use Declarations Filed Under Seal to explain the reasoning behind your discovery request.[2] If you give the court an idea as to why the information is requested, the court would be more inclined to grant your request.

Penal Code section 1054.1 lists the disclosure requirements of the prosecuting attorney.  Suppression of evidence favorable to the defense is a violation of the Due Process clause of the 5th and 14th Amendment, irrespective of the good or bad faith of the prosecution.[3]

Evidence is “favorable” to the defendant if it either helps the defendant or hurts the prosecution[4], if it mitigates punishment[5], if it directly opposing guilt[6], if it indirectly opposing guilt[7], if it supports defense testimony[8], if it supports a defense motion that would weaken the prosecution’s case[9], or if impeaches a prosecution witness’s credibility[10].

The prosecution must, without request, disclose all substantial, material evidence favorable to an accused, where such evidence relates directly to the question of guilt, to matters relevant to punishment, or to the credibility of a material witness.[11]

If it can be established that the prosecution team withheld evidence in bad faith with the intent to conceal the information, see Penal Code § 141(c):

“A prosecuting attorney who intentionally and in bad faith alters, modifies, or withholds any physical matter, digital image, video recording, or relevant exculpatory material or information, knowing that it is relevant and material to the outcome of the case, with the specific intent that the physical matter, digital image, video recording, or relevant exculpatory material or information will be concealed or destroyed, or fraudulently represented as the original evidence upon a trial, proceeding, or inquiry, is guilty of a felony punishable by imprisonment pursuant to subdivision (h) of Section 1170 for 16 months, or two or three years.”

Evidence Code Section 721 Should Be Used To Claim The Necessity For The Discovery Upon Which The Expert Based His Opinion

“(a) Subject to subdivision (b), a witness testifying as an expert may be cross-examined to the same extent as any other witness and, in addition, may be fully cross-examined as to (1) his or her qualifications, (2) the subject to which his or her expert testimony relates, and (3) the matter upon which his or her opinion is based and the reasons for his or her opinion.”

Under the Due Process Clause, the government has the obligation to disclose to the defendant evidence in their possession that is favorable to the accused and material to the issues of guilt or punishment.[12] The defendant generally is entitled to discovery of information that will assist in his defense or be useful for impeachment or cross-examination of adverse witnesses.[13] A motion for discovery must describe the information sought with specificity and provide a plausible justification for disclosure.[14]

Gang Experts Are Experience-only Experts

Daubert requires that expert testimony be both reliable and relevant, and those requirements are enforced by the trial judge, serving as a “gatekeeper.”[15] Daubert standards apply to non-scientific experts in California.[16] In describing the “gatekeeping responsibility” of California judges, the court noted that similar terms have been used to describe the responsibility of Federal judges and the court did nothing to suggest that the terms do not have the same meaning.[17]

Many California cases before Daubert have addressed the reliability of information used as the foundation for the expert’s opinion. Gang expert’s testimony held insufficient because expert relied on hearsay statements from unidentified gang members.[18] Defense gang expert’s testimony was properly excluded because the expert refused to disclose the names of the people he spoke to that formed the basis for his opinion.[19] Gang expert’s testimony held insufficient because the witness had no personal knowledge and relied on vague and secondhand information.[20] Court must apprised of the basis for the gang expert’s opinion to be able to assess its reliability.[21] An “‘expert's opinion is no better than the facts on which it is based.’ [Citation.]”[22] Expert’s opinion that minor’s specific intent in possessing a knife was to protect street gang’s members was improperly admitted because the opinion was supported only by the expert’s personal belief and no corroborating evidence.[23] Expert testimony on gang activity rejected as unreliable because information establishing opinion’s reliability was never elicited.[24] Gang expert’s testimony was insufficient to sustain a conviction when the “underlying premise” of the expert’s opinion was “factually incorrect.”[25]

Foundation For Gang Expert Testimony Is Necessary To Decide Evidentiary Issues

Evidence Code section 802 allows the court to inquire into the expert’s reasons for an opinion prior to the expert testifying during trial. Sargon discusses the power of the court in limiting an expert’s testimony under Evidence Code section 802:

“This section indicates the court may inquire into the expert's reasons for an opinion. It expressly permits the court to examine experts concerning the matter on which they base their opinion before admitting their testimony. The reasons for the experts' opinions are part of the matter on which they are based just as is the type of matter. Evidence Code section 801 governs judicial review of the type of matter; Evidence Code section 802 governs judicial review of the reasons for the opinion. ‘The stark contrast between the wording of the two statutes strongly suggests that although under section 801(b) the judge may consider only the acceptability of the generic type of information the expert relies on, the judge is not so limited under section 802.’ [citation]”[26]

When a gang expert testifies concerning his opinion, the basis of the opinion must be established to the court as being based on reliable information. Information obtained from expert’s own investigations or obtained from law enforcement officers, including police reports may be reasonably relied upon.[27] Information obtained from expert’s work on gang task force, training seminars, on-the-job training, and investigations, as well as books and journals on gangs may be reasonably relied upon.[28] Gang expert cannot rely on the opinions of other experts.[29] Also, while experts may offer opinions and the reasons for their opinions, they may not under the guise of reasons bring before the trier of fact incompetent hearsay evidence.[30]

The California Supreme Court addressed what can constitute incompetent hearsay under the Confrontation Clause in People v. Sanchez.[31] In Sanchez, the Supreme Court held that:

  1. Statements that an expert relied on to opine on defendant's gang membership were hearsay; when an expert relates case-specific out-of-court statements and treats the content of those statements as true and accurate to support expert's opinion, it cannot logically be maintained that the statements are not being admitted for their truth, and if the expert seeks to relate testimonial hearsay, there is a potential Confrontation Clause violation.
  2. The Confrontation Clause was violated by the expert's testimony about defendant's five prior police contacts, which the expert learned about through police reports and presented as true statements of fact without independent proof; the statements were testimonial because the reports were compiled during police investigation of the completed crimes.

The Supreme Court held that “case-specific” out-of-court statements run afoul to the Confrontation Clause when the expert relies are such statements to support his opinion.[32]

What constitutes “case specific” out-of-court statements? Facts are only “case specific” when they relate “to the particular events and participants alleged to have been involved in the case being tried,” which in Sanchez were the defendant's personal contacts with police reflected in the hearsay police reports, STEP notice, and FI card.[33] An expert may still rely on general “background testimony about general gang behavior or descriptions of the … gang's conduct and its territory,” which is relevant to the “gang's history and general operations.”[34]

The Sanchez opinion led to a plethora of litigation concerning the issue of expert testimony. Information obtained through websites that provide the chemical compound of pills possessed by the defendant is “case specific” unreliable and inadmissible hearsay.[35] Predicate acts, statements of membership and gang affiliation are types of case-specific facts which trigger a Sanchez analysis via the Confrontation Clause.[36] Sanchez applies to trials on the gang injunction itself as well.[37]

Case specific out-of-court statements are admissible if they do not constitute hearsay (i.e. gang expert based his opinion on personal observations and personal contacts with the defendant he noted on the FI card used.[38]) General background testimony can include the particular gang’s operations, signs or symbols, primary activities, and pattern of criminal activities, when unrelated to the defendant or the current event serving as the basis of the trial. The expert testimony may rely of such hearsay when testifying in general terms.[39]

The Sufficiency Of The Evidence Supporting The Gang Expert’s Opinion Must Be Weighed Under An Evidence Code Section 352 Analysis Before The Expert’s Testimony Is Before The Jury

Evidence Code section 352 allows trial judge to limit testimony where its prejudicial value substantially outweighs its relevance. Defendant's gang membership is inadmissible when it serves no evidentiary function other than to allow “unreasonable inferences … that [defendant] [is] guilty of the offense charged on the theory of ‘guilt by association’.”[40]

A gang expert testimony must be supported by sufficient facts. “[E]vidence of gang membership cannot itself prove that an individual has entered a criminal agreement to attack members of rival gangs.”[41] When an expert offers an opinion based solely on the fact that two gang members possessed illegal property together is insufficient to convict under 186.22(b) as such a holding would convert 186.22(b) into a general intent crime.[42] Gang expert’s testimony that crime was one of the gang’s signature crimes without evidence demonstrating how the manner of committing the crime was distinct to the gang did nothing more than improperly inform the jury of how the expert believed the case should be decided.[43] “Mere active and knowing participation in a criminal street gang is not a crime.”[44] When the defendant acts alone and is a gang member, such evidence alone is insufficient to satisfy the specific intent required under 186.22(b).[45] “[G]ang evidence standing alone cannot prove a defendant is an aider and abettor to a crime.”[46]

The prosecution must demonstrate that the crime was committed by a single “criminal street gang.” If more than one subset is involved, the prosecution must demonstrate evidence of collaboration or organization, or the sharing of material information among the subsets, or the subsets are part of a hierarchy organization, or members exhibit behavior showing self-identification with larger group. It is not enough that the group shares a common name, identifying symbols, and a common enemy.[47]

Evidence Code Section 771 Can Also Be Argued To Get The Information Before The Expert Testifies

EC 771 States:

    1. Subject to subdivision (c), if a witness, either while testifying or prior thereto, uses a writing to refresh his memory with respect to any matter about which he testifies, such writing must be produced at the hearing at the request of an adverse party and, unless the writing is so produced, the testimony of the witness concerning such matter shall be stricken.
    2. If the writing is produced at the hearing, the adverse party may, if he chooses, inspect the writing, cross-examine the witness concerning it, and introduce in evidence such portion of it as may be pertinent to the testimony of the
    3. Production of the writing is excused, and the testimony of the witness shall not be stricken, if the writing:
      1. Is not in the possession or control of the witness or the party who produced his testimony concerning the matter; and
      2. Was not reasonably procurable by such party through the use of the court's process or other available means

Waiting until trial to request or provide discovery frustrates the judicial process. A party is entitled to the documents used by an adverse witness to refresh their recollection; however, to request the remedy to strike the testimony for failure to produce the documents cannot be a ploy to manufacture an appealable issue. The adverse party should request the discovery before trial and not use section 771 to manipulate judicial processes to unnecessarily force the judge to follow Penal Code section 1050.[48]


  • [1] Penal Code section 1054.5(b).
  • [2] California Rules of Court, rule 8.46 governs how motions are received under seal by the court.
  • [3] Brady v. Maryland (1963) 373 U.S. 83, 87; U.S. v. Agurs (1976) 427 U.S. 97, 107.
  • [4] In re Sassounian (1995) 9 Cal.4th 535, 543-544.
  • [5] Brady v. Maryland, supra.
  • [6] People v. Jackson (1991) 235 Cal.App.3rd 1670, 1676.
  • [7] People v. Clark (1992) 3 Cal.4th 41, 133-134; People v. Kaurish (1990) 52 Cal.3rd 648, 684-687.
  • [8] People v. Collie (1981) 30 Cal.3rd 43, 54.
  • [9] United States v. Gamez-Orduno (9th Cir. 2000) 235 F.3d 453, 461.
  • [10] United States v. Bagley (1985) 473 U.S. 667, 676
  • [11] Brady v. Maryland, supra; People v. Ruthford (1975) 14 Cal.3d 399.
  • [12] Strickler v. Greene (1999) 527 U.S. 263, 280-282; Pennsylvania v. Ritchie (1987) 480 U.S. 39, 57.
  • [13] People v. Memro (1985) 38 Cal.3d 658, 677.
  • [14] People v. McPeters (1992) 2 Cal.4th 1148, 1171.
  • [15] Daubert v. Merrell Dow Pharms., Inc. (1993) 509 U.S. 579.
  • [16] See Sargon Enters., Inc. v. University of S. Cal. (2012) 55 Cal.4th 747.
  • [17] Id., at 769 fn 5.
  • [18] In re Leland D. (1990) 223 Cal.App.3d 251, 259.
  • [19] People v. Price (1991) 1 Cal.4th 324, 420.
  • [20] In re Nathanial C. (1991) 228 Cal.App.3d 990, 1003.
  • [21] People v. Gardeley (1996) 14 Cal.4th 605, 620.
  • [22] People v. Gardeley (1996) 14 Cal.4th 605, 618.
  • [23] In re Franks S. (2006) 141 Cal.App.4th 1192.
  • [24] In re Alexander L. (2007) 149 Cal.App.4th 605, 612.
  • [25] In re Daniel C. (2011) 195 Cal.App.4th 1350. 1363-1364.
  • [26] Sargon Enterprises, supra, 55 Cal.4th at 771.
  • [27] People v. Williams (2009) 170 Cal.App.4th 587, 622.
  • [28] People v. Valadez (2013) 220 Cal.App.4th 16, 29.
  • [29] Evidence Code section 804; Whitfield v. Roth (1974) 10 Cal.3d 874, 895; People v. Campos (1995) 21 Cal.App.4th 304, 308.
  • [30] In re Nathanial C., supra, 228 Cal.App.3d at 1004.
  • [31] People v. Sanchez (2016) 63 Cal.4th 665.
  • [32] Id., at 686.
  • [33] Id., at 676.
  • [34] Id. at 698.
  • [35] People v. Stamps (2016) 3 Cal.App.5th 988, 996-997.
  • [36] People v. Vega-Robles (2017) 9 Cal.App.5th 382, 413-414; see also People v. Ochoa (2017) 7 Cal.App 5th 575, 577.
  • [37] People ex rel. Reisig v. Acuna (2017) 9 Cal.App.5th 1.
  • [38] People v. Meraz (2016) 6 Cal.App.5th 1162, 1174.
  • [39] Id., at 1175.
  • [40] In re Wing Y. (1977) 67 Cal. App. 3d 69, 79.
  • [41] U.S. v. Garcia (9th Cir. 1998) 151 F.3d 1243, 1246.
  • [42] People v. Ramon (2009) 175 Cal.App.4th 843.
  • [43] People v. Ochoa (2009) 179 Cal.App.4th 650.
  • [44] People v. Rodriguez (2012) 55 Cal.4th 1125, 1130.
  • [45] People v. Rios (2013) 222 Cal.App.4th 542.
  • [46] People v. Guillen (2014) 227 Cal.App.4th 934, 992.
  • [47] People v. Prunty (2015) 62 Cal.4th 59.
  • [48] People v. Blackwell (1981) 117 Cal.App.3d 372.