A fourth photograph, showing a stretch of railroad tracks, was also identified by Marina Oswald as having been taken by her husband, presumably in connection with the Walker shooting.725 Investigation determined that this photograph was taken approximately seven-tenths of a mile from Walker's house.726 Another photograph of railroad tracks found among Oswald's possessions was not identified by his wife, but investigation revealed that it was taken from a point slightly less than half a mile from General Walker's house.727 Marina Oswald stated that- when she asked her husband what be had done with the rifle, he replied that he had buried it in the ground or hidden it in some bushes and that he also mentioned a railroad track in this connection. She testified that several days later Oswald recovered his rifle and brought it back to their apartment.728

Firearms identification.--In the room beyond the one in which General Walker was sitting on the night of the shooting the Dallas police recovered a badly mutilated bullet which had come to rest on a stack of paper.729 The Dallas City-County Investigation Laboratory tried to determine the type of weapon which fired the bullet. The oral report was negative because of the battered condition of the bullet.730 On November 30, 1963, the FBI requested the bullet. for ballistics examination; the Dallas Police Department forwarded it on December 2, 1963.731

Robert A. Frazier, an FBI ballistics identification expert, testified that he was "unable to reach a conclusion" as to whether or not the bullet recovered from Walker's house had been fired from the rifle found on the sixth floor of the Texas School Book Depository Building. He concluded that "the general rifling characteristics of the rifle * * * are of the same type as those found on the bullet * * * and, further, on this basis * * * the bullet could have been fired from the rifle on the basis of its land and groove impressions." 732 Frazier testified further that the FBI 'avoids the category of "probable" identification. Unless the missile or cartridge case can be identified as coming from a particular weapon to the exclusion of all others, the FBI refuses to draw any conclusion as to probability.733 Frazier testified, however, that he found no microscopic characteristics or other evidence which would indicate that the bullet was not. fired from the Mannlicher-Carcano rifle owned by Lee Harvey Oswald. It was a 6.5-millimeter bullet and, according to Frazier, "relatively few" types of rifles could produce the characteristics found on the bullet.734

Joseph D. Nicol, superintendent of the Illinois Bureau of Criminal Identification and Investigation, conducted an independent examination of this bullet and concluded "that there is a fair probability" that the bullet was fired from the rifle used in the assassination of President Kennedy.735 In explaining the difference between his policy and that of the FBI on the matter of probable identification, Nicol said:

I am aware of their position. This is not, I am sure, arrived at without careful consideration. However, to say that because one does not find sufficient marks for identification that it is a negative,