(Testimony of John F. Gallagher)
Mr. Gallagher.
this analysis, to express an opinion as to whether the person from whose hands these casts were made had fired a weapon.
Mr. Gallagher.
It is my opinion that the person from whom these casts were removed may have either handled a fired weapon, or fired a weapon.
Mr. Redlich.
I would like to introduce into the record a letter which I have marked Gallagher Exhibit No. 1.
(Gallagher Exhibit No. 1 was marked for identification.)
Mr. Redlich.
This is a letter from FBI Director J. Edgar Hoover to J. Lee Rankin, general counsel of this Commission. Are you familiar with the contents of this letter, Mr. Gallagher?
Mr. Gallagher.
Yes, sir.
Mr. Redlich.
You will note that this letter indicates a variety of substances which contain the element barium, the element antimony, and substances which contain the elements barium and antimony.
The last question I asked you, Mr. Gallagher, was whether you could make a judgment as to whether a person from whose hands these casts were made had fired a weapon or handled a fired weapon, and you indicated that on the basis of these tests you could make such a judgment.
The question I now ask you is in light of the contents of the letter which has been designated as Gallagher Exhibit No. 1, are you able to isolate the source of the elements barium and antimony which you found on the hand casts as coming from the primer residues rather than from the substances which are described in Gallagher Exhibit No. 1 ?
Mr. Gallagher.
It is true that there are common commercial products which contain barium and which contain antimony.
Mr. Redlich.
And which contain barium and antimony together?
Mr. Gallagher.
And also which contain barium and antimony together. However, before these elements can contaminate the hands or person--hands or body of an individual--they must be accessible so they can adhere by mechanical adhesion to the individual. Under normal circumstances, most of the ingredients mentioned in Exhibit No. 1.
Mr. Redlich.
Excuse me--could you refer to that as Gallagher Exhibit No. 1?
Mr. Gallagher.
Gallagher Exhibit No. 1, is not normally in the form which will permit contamination by this mechanical adhesion.
Mr. Redlich.
Are you generally familiar with the test which is commonly referred to as the paraffin test, which tests paraffin casts for nitrate residues?
Mr. Gallagher.
Yes, sir.
Mr. Redlich.
As I understand it, Mr. Gallagher, one of the reasons why this test is considered unreliable for purposes of determining whether or not someone has fired a weapon is the fact that the elements which react with the reagents in the paraffin test are found in a variety of common substances. Is that correct?
Mr. Gallagher.
The diphenylamine or the diphenylbenzadene tests are not specific. They react with many ingredients and for this reason the results obtained from such tests are difficult to interpret.
Mr. Redlich.
And when I asked you to evaluate the results of the neutron activation test performed on the hand casts in the light of the contents of Gal-lagher Exhibit No. 1, do I understand your answer to be that in the case of the neutron activation analysis it is possible to make a valid determination as to the presence of the elements barium and antimony, notwithstanding the fact that the elements barium and antimony are found in common substances and not merely found in primer residues.
Mr. Gallagher.
The determination of barium and antimony by neutron activation analysis is specific. Although there are commercial products which contain the elements barium and antimony, these components in many of these commercial products are not as available for contaminating purposes as are nitrates and oxidizing agents detected by the diphenylamine or diphenylbenzi-dine tests.
Mr. Redlich.
So that the differences between the neutron activation analysis and the paraffin test for nitrate residues relate both to the question of the availability of the nitrates and oxidizing agents in the paraffin test as compared to the barium and antimony in the neutron activation analysis, and also to the fact that in the paraffin test for nitrate residues, the result is not necessarily
|
