Data Analytics Expert’s Analysis of Inmate Records Deemed Admissible
Posted on November 17, 2025 by Expert Witness Profiler
Plaintiffs Orellana and Hernandez brought this suit against Defendants on behalf of a class of all persons who, from July 18, 2014 through November 15, 2018, were detained by the Suffolk County Sheriff’s Office (“SCSO”) pursuant to an ICE immigration detainer request after the SCSO’s detention authority had expired, alleging violations of their rights under the Fourth and Fourteenth Amendments of the United States Constitution and under the First Article of the New York State Constitution.
Plaintiffs retained Sean M. Kruskol to calculate the duration in hours that each class member was held in custody by the Suffolk County Sheriff’s Office (“SCSO”) under a detainer and administrative warrant issued by Immigration and Customs Enforcement (“ICE”).
He purported to do so by analyzing the file of inmate records—known as an “inmate jacket”—maintained for each class member by SCSO, and determining “a) the time when the SCSO’s records indicate an individual would have been released but for the existence of an ICE detainer; and b) the time when the SCSO’s records indicate an individual was transferred into ICE custody.”
However, Defendants filed a motion to preclude “[Class] Plaintiffs’ expert Kruskol from offering testimony or opinions in this matter” under Rule 702 and the Daubert standard.
Data Analytics Expert Witness
Sean M. Kruskol is a Certified Public Accountant (‘CPA’), Chartered Global Management Accountant (‘CGMA’) and a Certified Fraud Examiner (‘CFE’) with more than a decade of experience leading complex, large-scale data analytics in litigation and investigations across industries.
Discussion by the Court
Defendants sought to exclude Kruskol’s expert testimony as (1) outside his area of expertise, (2) based on flawed methodology, and (3) unhelpful to the jury.
After conducting the appropriate review under Rule 702 and under Daubert and its progeny, the Court determined that Defendants’ objections go to the weight, rather than admissibility, of Kruskol’s expert testimony. Kruskol is a qualified expert in data analytics with ample experience analyzing large datasets and deriving conclusions therefrom.
Moreover, his expert testimony relied on sound methodology and data. Kruskol tested the reasonableness of his results by comparing the computed extended detentions intervals to how SCSO’s documents described their internal operational expectations (including the 48-hour detainer language) and performed adjustments and sensitivity checks for administrative processing time.
To the extent Defendants disagree with Kruskol’s conclusions, Defendants will, for instance, have the opportunity to cross-examine Kruskol.
Finally, Kruskol’s testimony is sufficiently likely to assist the jury by presenting a coherent summary of “thousands of pages of technical inmate records” and purporting to “accurately identify and reconcile timestamps across multiple record types and fields.”
Held
The Court denied the motion to exclude Sean Kruskol’s expert testimony.
Key Takeaway:
The test to admit expert testimony under Rule 702 and under Daubert requires an analysis of the following considerations: (1) whether the witness is qualified to be an expert; (2) whether the opinion is based upon reliable data and methodology; and (3) whether the expert’s testimony on a particular issue will assist the trier of fact.
Kruskol is a qualified expert in data analytics with ample experience analyzing large datasets and deriving conclusions therefrom. His expert testimony relied on sound methodology and data. Moreover, Kruskol’s testimony is sufficiently likely to assist the jury.
Case Details:
| Case Caption: | Castaneda V. County of Suffolk |
| Docket Number: | 2:17cv4267 |
| Court Name: | United States District Court for the Eastern District of New York |
| Order Date: | October 31, 2025 |
