Joshua M. Rogers of Memphis, Tennessee, pleaded guilty yesterday to a violation of 18 U.S.C. § 1512(c) for his role in destroying evidence related to a police officer’s fatal shooting of a man identified by the initials R.H. With the plea, Rogers admitted that he acted to impair the integrity or availability of R.H.’s body for use in an official proceeding and, in so doing, shield his co-defendant from criminal liability.