District court's denial of defendant's petition for habeas corpus is reversed and remanded, where: 1) defendant was not deprived of his due process rights because it was objectively reasonable for the Superior Court to decide that a rational jury could have found defendant guilty of second-degree murder, robbery, and conspiracy to commit robbery beyond a reasonable doubt; but 2) defendant's Sixth Amendment confrontation right was violated when his non-testifying co-defendant's confession was admitted against him at their joint trial and his motion to sever was denied, and this error was not harmless.