William Brenner, Peter McCullum, and Dominic Constantino, all of whom worked at the front benches with Pelser, were brought in as defense witnesses to contradict Pelser’s story, but their effect was lessened by the tidy mechanics of legal procedure that postpones the appearance of rebuttal witnesses until the prosecution has finished its case. So it was not until two weeks later, when the details of Pelser’s testimony were overlaid by that of a score of other witnesses, that Brenner took the stand. He too, after he had heard shots, looked through the partially opened center window and saw a man “sinking—sinking.” Pelser had not been near the window. After McCullum had raised the sash he had slammed it down again and yelled “Duck!” and they had all got down behind the benches. Under cross-examination Brenner admitted he really did not know where Pelser was when he himself was looking through the window. McCullum, following Brenner, was not sure where Pelser was either, but Constantino was certain that when the shooting started Pelser was “right down under the bench.” Afterward Pelser had told them: “I did not see any of the men but I got the number of the car.” Constantino admitted he had not given any thought to where Pelser was until he had read the latter’s testimony in the newspaper two weeks before. Then he had gone to the Sacco-Vanzetti Defense Committee and volunteered his information. At first he maintained that Pelser was at his workbench three windows down when McCullum had thrown up the sash, but Katzmann finally forced him to admit that he really did not know where Pelser was or whether he might have opened another window. The appearance of Hans Behrsin, the Slater chauffeur, was unsatisfactory to the prosecution. All he could say was that the two men he had seen sitting on the Rice & Hutchins fence as he drove past in the Marmon “seemed to be pretty well light-complexioned fellows.” He had not noticed their features, and the district attorney did not even bother to ask him to identify the defendants.