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U.S. v. Casey, 928 F.Supp.2d 397 (D.P.R. 2013)

Case (cite)
U.S. v. Casey, 928 F.Supp.2d 397 (D.P.R. 2013)
Puerto Rico
Type of proceeding
Type of claim
Type of claim (second claim)
Expert evidence ruling reversing or affirming on appeal:
What was the ruling?
Type of evidence at issue:
Firearms identification
Defense or Prosecution Expert
Name of expert(s) who were the subject of the ruling
Edward Perez-Benitez
Summary of reasons for ruling
Defendant argued that the expert's testimony should be limited based on 3 district court cases limiting testimony based on the 2008 NAS report expressing concerns about the reliability of AFTE theory. The court distinguished the three district court cases relied upon and cites Dr. Rolph (chairman of the group that produced the 2008 report) saying that the report did not address legal admissiblity. The court declines to follow sister court precedent and does not limit testimony.
The jurisdiction’s standard for expert admissibility at the time – list all that apply: (Frye), (Daubert), (Post-2000 Rule 702), (Other)
Second standard
Rule 702
Did lower court hold a hearing
Names of prosecution expert(s) two testified at hearing
Statement of Dr. Rolph (chairman of group that produced 2008 NAS report)
Names of defense expert(s) who testified at hearing (or None).
Discussion of 2009 NAS Report (NAS2009)
Discussion of 2016 PCAST report (PCAST)
Discussion of error rates / reliability
Frye Ruling
Limiting testimony ruling
Language imposed by court to limit testimony
Ruling based in prior precedent / judicial notice
Daubert ruling emphasizing – which factors – (list 1-5)
Ruling on qualifications of expert
Ruling on 702(a) – the expert will help / assist the jury
Ruling on 702(b) – the testimony is based on sufficient facts or data
Ruling on 702(c) – the testimony is the product of reliable principles and methods
Ruling on 702(d) – reliable application of principles and methods to the facts of the case


Dr. Rolph’s statements greatly undermine the portions of the 2008 NAS report upon which defendant and the Glynn, Taylor and Willock courts rely. Moreover, defendant’s employment of an expert witness who employed the AFTE Theory further illegitimizes his current, untimely objection5 Accordingly, the Court declines to follow sister courts who have limited expert testimony based upon the 2008 and 2009 NAS reports and, instead, remains faithful to the long-standing tradition of allowing the unfettered testimony of qualified ballistics experts




Dr. Pérez is duly qualified as a ballistics and firearms expert under Rule 702 and Daubert and may testify accordingly without qualification of his degree of certainty.