The third in a three-part series identifying the witnesses whose depositions are commonly taken in cases where electronically stored information will shape settlement or trial outcomes.

Trial counsel’s ability to make skilled use of electronically stored information is often outcome-determinative in modern litigation. ESI, however, can be difficult to locate within an opponent’s often sprawling computer network; and, when found, faces novel evidentiary challenges to ensure admissibility at trial. These problems are typically solved pretrial with deposition support from five categories of witnesses: Rule 30(b)(6) witnesses, party electronic document custodians, non-party electronic document custodians, forensic experts, and former employees.

A 2018 survey of litigators, conducted by Bloomberg Law, found that that the need to manage ESI was the leading reason why attorneys are conducting more depositions than prior years.

Prior posts discussed the significance of Rule 30(b)(6) witnesses and electronic document custodians (both party custodians and non-party custodians who may, for example, be employed by cloud service providers or telecommunications companies not subject to any party’s direct control).

This post addresses the last two witness categories whose depositions can turn ESI in counsel’s favor: forensic experts and former employees.

Most people readily appreciate the significance of non-electronic evidence: a handwritten letter, an image depicting a physical injury or damage to property, an eyewitness account of significant events. These kinds of evidence are all within a judge or juror’s realm of experience, often requiring little supporting explanation.

Not so with electronically stored information. In many cases, the significance of ESI uncovered during pretrial discovery will not be apparent to a lay person without supporting, explanatory testimony from an expert witness.

Deposing the Forensic Expert

For this reason, the value of ESI in litigation can be strengthened with deposition testimony from expert witnesses and, in some cases, testimony from a representative from a party’s own electronic discovery vendor. Forensic inspections of computer networks typically involve the use of sophisticated software programs that attempt to identify relevant files and recover deleted files. A capable forensic expert can unearth a case-changing document, find evidence of spoliation by the opposing party, or explain the significance of critical electronic information that would have gone unnoticed by nontechnical members of the litigation team.

An electronic discovery expert can also be used defensively. Expert testimony can be offered regarding the sufficiency of a party’s ESI production efforts. In the case of a party’s own electronic discovery vendor, this testimony will be based on the expert’s own participation in managing the electronic discovery process.

In Procaps S.A. v. Patheon Inc., No. 12-24356 (S.D. Fla. Apr. 24, 2015), the district court ordered the deposition of a computer forensic expert, in order to help the court decide whether files had been deleted by the plaintiff.

Finally, good forensic experts are good communicators. They can convincingly explain novel concepts and digital technologies outside of a lay person’s common understanding, often better than an attorney or the electronic document custodian.

Former Employees

The final category of witness that litigation counsel should consider deposing are former employees. These individuals, while no longer employed by a party, may nonetheless possess crucial evidence relevant to the litigation. Laptop computers, thumb drives, and cellphones often leave the organization when employees move on to another job. A thorough Rule 30(b)(6) deposition will often uncover the identities of these individuals — persons who may possess relevant ESI but are no longer under the direct control of the opposing party.

Former employees may also have served as custodians of relevant ESI during periods of time relevant to the litigation. As such, they are potential witnesses needed to give substantive testimony, to identify or produce relevant ESI not in the organization’s possession, or to authenticate ESI provided in discovery.

Former employees are potentially a source of information that cannot be directly influenced by parties to the litigation. While some former employees will be encumbered by nondisclosure agreements and confidentiality agreements, many will not. And counsel may find that the interests of former employees do not align precisely with the employer, thus offering an opportunity to acquire unbiased and helpful evidence.


Forensic experts and former employees of a litigation opponent can be a fruitful source of objective and persuasive evidence regarding the significance of ESI produced during pretrial discovery. Their testimony, whether obtained via deposition or during trial, supplies the fact-finder with information necessary for a complete understanding of the electronic evidence in the case.

Download our ESI: The Litigation Game Changer Infographic.

Related Posts: