Archive | expert witnesses

Tuesday, November 14th, 2023

Supreme Court grants certiorari to an alleged drug courier (challenging a federal drug conviction) because the prosecution used an “expert witness” to rebut her defense that she didn’t know about the drugs that were hidden inside her car, which she said belonged to her boyfriend. Petitioner says the “expert” testimony violated Fed.R.Evid. 704(b).

The Supreme Court granted certiorari in Diaz v. United States, No. 23-14 (cert. granted, Nov. 13, 2023).

Discussions and relevant cert. papers are available here:

The petition for certiorari frames the “Question Presented” as follows:

Federal Rule of Evidence 704(b) provides: “In a criminual case, an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that constitutes an element of the crime charged or of a defense. Those matters are for the trier of fact alone.” Fed.R.Evid.704(b).

The question is: In a prosecution for drug trafficking —— where an element of the offense is that the defendant knew she was carrying illegal drugs —— does Rule 704(b) permit a governmental expert witness to testify that most couriers know they are carrying drugs and that drug-trafficking organizations do not entrust large quantities of drugs to unknowing transporters?


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Categories: expert witnesses, Rule 704(b)

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Friday, March 3rd, 2023

Circuit rejects new trial bid, despite evidentiary errors and refusal to voir dire on “antisemitic bias.”

In United States v. Mendlowitz, No. 21-2049-cr (2d Cir. March 2, 2023) (summary order), the Second Circuit affirms the defendant’s wire fraud convictions, despite possible evidentiary errors and the district court’s refusal to ask about “potential antisemitic bias” during jury selection.

On appeal following trial, the defendant challenged the district court’s exclusion of a proffered expert witness and a recorded conversation between the defendant and a cooperating witness. The Circuit largely agreed with defendant’s arguments: it recognized that, contra the district court, the proffered expert testimony about standard industry practices would have been relevant to the defendant’s good faith defense. The expert testimony also would have provided relevant information outside the average juror’s knowledge and beyond any government witness testimony.

With respect to the recorded conversation, the defendant argued that it reflected his state of mind at the time of the charged conduct and supported his defense. The district …

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Categories: expert witnesses, harmless error, jury selection, voir dire

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Tuesday, September 20th, 2016

White House Report: “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature Comparison Methods.”

The President’s Council of Advisors on Science and Technology today released a report entitled “Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature Comparison Methods.”  You can access the report here.  According to a White House press release, “the study aims to help close the gaps for a number of ‘feature-comparison’ methods — specifically, methods for comparing DNA samples, bitemarks, latent fingerprints, firearm marks, footwear, and hair.”  The report contains a number of recommendations directed at the FBI Laboratory, the Attorney General, and the judiciary as well as the National Institute of Standards and Technology (NIST) and the White House Office of Science and Technology Policy (OSTP).

In cases with feature comparison evidence that was not gathered and evaluated as recommended in the report, the report may support the exclusion of the evidence or provide a fruitful area of cross examination.  It should also help limit the opinions …

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Categories: DNA, expert witnesses, firearms

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Tuesday, May 10th, 2016

Judge Rakoff Rejects Proposed Handwriting Expert Testimony

In an opinion released May 6, in the case Almeciga v. Center for Investigative Reporting, 15-cv-4319, SDNY Judge Jed S. Rakoff granted a defense motion to exclude proposed expert handwriting analysis testimony, holding that “handwriting analysis in general is unlikely to meet the admissibility requirements of Federal Rules of Evidence 702.”  The opinion documents the development of handwriting analysis as a forensic field and its history in the courts before analyzing the Daubert and Kumho Tire factors.  See Opinion, 17-43.  The Court concludes that handwriting analysis “bears none of the indicia of science and suggests, at best, a form of subjective expertise,”  Opinion at 26.  “It remains the case,” the Court explains, “that the methodology has not been subject to adequate testing or peer review, that error rates for the task at hand are unacceptably high, and that the field sorely lacks internal controls and standards” and that “as …

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Categories: expert witnesses

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Tuesday, March 29th, 2016

Woe Betide Those Who Park on the Wrong Side of the Street (and those who produce child pornography)


No relevant opinions today; two summary orders.

In United States v. Grady, Syracuse police noticed that Grady’s car was parked in violation of the city’s odd/even street parking rules.  They approached the car, shone their flashlights inside and saw, in plain view, a bag of crack cocaine on Grady’s lap.  A loaded gun was also found in the car.

Assuming the officers’ approach of the car constituted a stop, the Court (Jacobs, Hall, Lynch, CJJ) held there was reasonable suspicion given the car’s being parked on the wrong side of the street.  Though a car isn’t “parked” if it’s stopped only to load or unload goods or passengers, the officers observed no such activity and the Court held they watched the car for long enough — 10 seconds — before deciding to approach.  “The officers were not required to conduct surveillance long enough to ‘rule out the possibility of …

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Categories: car stop, child pornography, expert witnesses, Fourth Amendment, reasonable suspicion, substantive reasonableness

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Sunday, October 19th, 2008

Expert Tease

United States v. Mejia, No. 05-2856-cr (2d Cir. October 6, 2008) (Jacobs, Parker, Hall, CJJ)

Here, the improper admission of “officer expert” testimony resulted in a new trial.


The defendants were convicted of participating in two drive-by shootings in connection with their membership in the MS-13 gang. One defendant was sentenced to sixty-three years’ imprisonment, the other to sixty.

A significant portion of the evidence against them, however, came from a New York State Police investigator who testified about the structure and organization of MS-13, as well as its “methods and activities, modes of communication and slang.” It turned out however, the officer’s sources for much of this information were suspect, including reports from other law enforcement officers, custodial statements from other gang members, internet research, and wiretaps that he listened to.

The Court’s Ruling

The court of appeals reversed, finding that much of the officer’s testimony was improper.…

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Categories: Crawford, expert witnesses, hearsay, Uncategorized

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Saturday, September 6th, 2008

A Family Affair

United States v. Yannotti, No. 06-5571-cr (2d Cir. September 4, 2008) (Katzmann, Parker, Raggi, CJJ)

Michael Yannotti was one of several Gambino crime family members accused of multiple violent acts – including extortion, loansharking and murder. After a jury trial, he was convicted of a RICO conspiracy, although the only predicates that the jury could agree that he committed were loansharking activities that had taken place eight years or more before he was indicted. The jury did not reach a verdict on a substantive RICO count, which the district court then dismissed on the ground that the government had failed to prove that Yannotti committed any predicate within the five-year statute of limitations. But the court did not dismiss the conspiracy count and, when it sentenced him, based its findings on conduct that the jury had not agreed that the government had proven. Yannotti received twenty years in prison, the …

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Categories: 1B1.2, expert witnesses, RICO, Uncategorized, wiretaps

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