388 A.2d 926 CLARENCE HARRIS JOHNSON v. STATE OF MARYLAND [No. 151, September Term, 1977.]Court of Appeals of Maryland. Decided July 17, 1978. CRIMINAL LAW — WITNESSES — Sequestration — Granting Of Request To Exclude Witnesses In Trial Is Mandatory And Not Discretionary — No Exception For A Principal Investigator — Maryland Rule 755. pp. […]