On January 30, 1947, P, along with Hough and Almeida, engaged in an armed robbery of a supermarket. An off-duty policeman, Ingling, who happened to be in the area with his wife and children, was shot and killed while attempting to thwart the escape of the felons. The evidence as to who fired the fatal shot was conflicting in P's 1948 trial. The court charged the jury that it was irrelevant who fired the fatal bullet: 'Even if you should find from the evidence that Ingling was killed by a bullet from the gun of one of the policemen, that policeman having shot at the felons in an attempt to prevent the robbery or the escape of the robbers, or to protect Ingling, the felons would be guilty of murder, or if they did that in returning the fire of the felons that was directed toward them.' P objected and took a specific exception to this part of the charge. P was convicted of first-degree murder, with punishment fixed at life imprisonment. P filed no post-trial motions and took no appeal. Nor did P initiate any post-conviction proceedings until the instant case. On February 4, 1966, P filed a petition for a writ of habeas corpus. P claims in part that he was denied his constitutional right to a fair trial by reason of the trial judge's charge to the jury, quoted above, which was allegedly inconsistent with the rule later announced by this Court in Commonwealth v. Redline, 391 Pa. 486, 137 A. 2d 472 (1958). The court denied the petition, and P appealed.