## Facts

- In a federal criminal prosecution, the government sought to introduce FBI Laboratory DNA evidence generated through PCR/STR (polymerase chain reaction/short tandem repeat) typing.
- The court conducted multiple pretrial evidentiary hearings on admissibility under Daubert and Federal Rule of Evidence 702.
- The government presented expert testimony from Dr. Bruce Budowle, an FBI DNA scientist, describing PCR amplification and STR analysis at 13 loci pursuant to FBI protocols, quality controls, and auditing.
- Budowle testified PCR was widely accepted; PCR/STR typing was supported by validation studies; and, assuming protocol compliance and proper calibration, analytical error was essentially zero.
- The defense presented expert testimony from Dr. Theodore Kessis, who challenged the reliability of PCR/STR typing as implemented, estimated an error rate of about 1 in 200, and criticized reliance on mass-produced reagent kits, alleged peer-review bias, limited empirical error data, and asserted protocol shortcomings.
- Before trial, the court denied the defense motion to suppress the DNA evidence and granted the government motion to admit it.
- After conviction, Carlton Ewell moved for a new trial under Federal Rule of Criminal Procedure 33, arguing admission of the PCR/STR DNA evidence failed Daubert and was erroneous.

## Issues

1. Whether FBI PCR/STR DNA typing, including the use of standardized kits and FBI laboratory protocols, was sufficiently reliable and relevant under Daubert and Federal Rule of Evidence 702 to be admitted.
2. Whether admission of the DNA evidence, if erroneous, warranted a new trial under Federal Rule of Criminal Procedure 33.

## Decision

- The court held the government’s PCR/STR DNA methodology satisfied Daubert and Rule 702 reliability requirements.
- The court found the method supported by testing, validation studies, quality controls, and general acceptance in the relevant scientific community.
- The court treated many defense criticisms (including asserted real-world error and alleged peer-review bias) as matters for cross-examination and competing expert testimony rather than exclusion.
- The court denied Ewell’s Rule 33 motion for a new trial.

## Legal Principles

- Under Federal Rule of Evidence 702 and Daubert, scientific expert testimony is admissible when grounded in reliable methodology and relevant to the factfinder’s task, considering factors such as testing, peer review/publication, known or knowable error rate, standards controlling operation, and general acceptance.
- The admissibility inquiry focuses on methodological reliability, not whether the expert’s ultimate conclusions are correct.
- Where a method is supported by validation and quality-control standards, challenges to implementation details or competing error-rate estimates typically go to weight rather than admissibility and are addressed through cross-examination and contrary evidence.
- A new trial under Federal Rule of Criminal Procedure 33 is not warranted absent a showing that the challenged evidentiary ruling was erroneous and sufficiently affected the verdict to justify relief.

## Conclusion

The court reaffirmed that FBI PCR/STR DNA typing, performed under validated protocols with quality controls, is reliable under Daubert and Rule 702, and it denied the defendant’s motion for a new trial based on the admission of that DNA evidence.


United States v. Ewell, 252 F. Supp. 2d 104 (D.N.J. 2003)