Gutshall (plaintiff) was driving a tractor-trailer when he was rear-ended by Robert Tapper (defendant), who was driving a tractor-trailer owned by New Prime, Inc. (New Prime) (defendant). Gutshall sued Tapper for negligence and sought to hold New Prime vicariously liable under the doctrine of respondeat superior, based on the fact that Tapper was acting within the scope of his employment with New Prime when the accident occurred. Gutshall served an interrogatory asking whether New Prime had conducted any surveillance of Gutshall and requesting that any related evidence be produced. New Prime had not conducted any surveillance at that time and responded that it had not. However, New Prime subsequently did engage in surveillance. Gutshall noticed and filed a motion to compel discovery responses and exclude the evidence on the ground that New Prime had failed to supplement its responses to the interrogatory as required by Federal Rule of Civil Procedure (FRCP) 26(e)(1). New Prime objected, asserting that it only intended to use the surveillance evidence for impeachment purposes and therefore was not obligated to turn the evidence over under FRCP 26(a)(3). New Prime further asserted the evidence was protected work product.