Rosengarten stated that the isolated gunshot remains found on the defendant's hair, hands, and clothes have no evidentiary value due to the possibility of secondary transfer both from the work environment and along the exhibit chain. According to him, it is impossible to know whether the policeman who sampled the defendant and the exhibits was not contaminated with gunshot remnants (p. 665 of Prut).
Rosengarten said that the accumulation of gunshot remains found on the defendant's body and clothes was of no significance. According to him, in order for the accumulation of gunshot remains to be meaningful, it is necessary to prove a connection between all the exhibits. He went on to say that in order to draw a conclusion from the accumulation of gunshot remains found on various exhibits, a statistical experiment should be conducted and the likelihood of the presence of gunshot remains on the exhibits should be examined (pp. 667-669 of the protégé).
Rosengarten said that a secondary transfer of gunshot remains to the defendant's clothes could not be ruled out because it was impossible to know what was in the vicinity where they were caught and what was about the policeman who caught them. According to him, a policeman carrying a weapon is considered a person contaminated with gunshot remnants (pp. 673-674 of Pruitt).
Rosengarten confirmed that the use of sterile gloves when making the samples reduces the risk of contamination of the exhibits and the defendant with the remnants of gunfire. He went on to say that changing gloves alone is not enough, and that the correct way to reduce the possibility of secondary infection is to wash the gloves before taking them off and then washing their hands (p. 675 of the protégé).
The prosecution presented Rosengarten with an article on the presence of remnants of shooting at police officers and police cars (P/102) and told him that an examination of 17 investigators at the scene did not find any remnants of gunfire on 14 of them. After Rosengarten was given the opportunity to review the article, he replied that there was still the possibility of a secondary transfer of gunshot remains by a single scene investigator (pp. 676-678 of Pruth). Rosengarten was presented with an article on the presence of gunshot remnants in vehicles and detention facilities (P/103) and was told that according to the results of the study described therein, the potential for the defendant to be contaminated with gunshot remnants was low, and in response he referred to an article from 2021 about which he claimed that in an examination of the general population with a low chance of encountering firearms, a 7% chance of contamination with gunshot remnants was found (p. 679 of Prout). When the expert was presented with another article (P/104) and was told that according to him the probability of finding the remains of one shooting by an innocent person was 0.17 and that the probability of finding two gunshot remains by an innocent person was 0.02, Rosengarten replied that he could not disagree or disagree with this determination (p. 684 of Prut).