Mr. CUNNINGHAM. It acts as a medium in which the foreign material is
picked up from the hands.
Mr. EISENBERG. When you add the reagent, what is considered to be a
positive reaction?
Mr. CUNNINGHAM. It turns a blue color.
Mr. EISENBERG. That is the cast? When you say "it," it is the cast?
Mr. CUNNINGHAM. Well, specks on the cast.
Mr. EISENBERG. Dots?
Mr. CUNNINGHAM. Yes, or an area of the cast. The theory of the test
is that it is a test for gunpowder residues. Now, that is the theory,
and it is fallacious, inasmuch as the reagents used in these two tests
are not specific for gunpowder residues. Now, it is true that the
nitrates and nitrites in gunpowder residues will react positively with
diphenylamine and diphenylbenzidine, but they are not specific. They
will react--these two reagents will react with most oxidizing agents.
Mr. EISENBERG. Can you give us a few examples?
Mr. CUNNINGHAM. Yes. Urine, tobacco, cosmetics, pharmaceuticals, soil,
fertilizer--I have a list here of the different families or classes of
compounds that will react.
In addition to nitrates and nitrites, substances such as dichromates,
permanganates, hypochlorites, periodates, some oxides, such as
selenium dioxide and so forth. Also, ferric chloride and chromates
and chlorates. The list of oxidizing agents is so large--that will
react--that you cannot specifically say it was a gunpowder residue.
Mr. CUNNINGHAM. Supposedly it is to determine whether or not a person
has fired a weapon. In actuality, in chemistry it is a good indication
that an oxidizing agent is present. The reagents have a valid use in a
chemistry laboratory.
Representative BOGGS. Let me put the question this way. Given a dozen
ordinary people in the ordinary walk of life, what would be the chance
of a positive reaction on any one of these 12 people?
Mr. CUNNINGHAM. Excellent, sir.
Mr. EISENBERG. Has the FBI performed an experiment to determine this?
Mr. CUNNINGHAM. Yes; we have. The early sets of tests we ran with
diphenylamine. And 17 men were involved in this test. Each man fired
five shots from a .38 caliber revolver. Both the firing hand and the
hand that was not involved in the firing were treated with paraffin
casts, and then those casts treated with diphenylamine. A total of
eight men showed negative or essentially negative results on both
hands. A total of three men showed positive results on the idle hand,
but negative on the firing hand. Two men showed positive results on
their firing hand and negative results on their idle hands. And four
men showed positive on both hands, after having fired only with their
right hands. That was the first test we ran.
The second test--we used people who had not washed their hands in any
way. They were going about their duties during the day. Their hands
were soiled. Nine people fired weapons out of 29--20 people just had
the casts made.
The first person fired a revolver. Both right hand and left hand were
positive. The second person fired a revolver. Both hands positive. A
person fired an automatic pistol, where you would not expect to find
residue. Both hands positive. Shooting with the right hand only, again
one with a revolver and three people firing automatics, all positive.
Shooting with the left hand only, one person with a revolver, one with
an automatic, both hands positive.
Now, of the 20 people that had not come in contact with a gun--they
definitely had just gone about their business--every one of them showed
positive tests on either or both hands. A heavy smoker, for instance,
would come up positive in the area of the hand where you expect to find
residues from firing a gun.
Representative FORD. That is the hand that you use for smoking?
Mr. CUNNINGHAM. That's correct. And I noticed you with your pipe. You
are also sure to react because you touch the tobacco in your pipe. You
do it unconsciously. During another test we performed recently I did
not know that the diphenylbenzidine was on the corner of the cast I was
trying to pick up to wash off. I just touched it, and both my fingers
which had touched my cigar turned a blue color. That is how sensitive
it is.
Now, of these 20 people--true there were some that had one hand that
did not get a reaction, but they all got a reaction, one hand or
another, or both.
Now, recently in connection with the assassination we made casts--the
three of us, Special Agents Frazier, Killion, and myself, for
neutron-activation. However, two of the casts we treated with
diphenylbenzidine. We obtained a cast of the left hand after firing
this particular revolver four times and reloading. We obtained a cast
of the right hand after firing that revolver four times, and reloading.
We treated both casts, fronts and backs with diphenylbenzidine. This
particular one was run on me. I washed my hands thoroughly with green
soap--and the green soap, by the way, did not react because we checked
it--the gauze used and the paraffin were all checked, to see if they
would react, and they did not. We found numerous, numerous reactions
on the casts of both hand. And I did not fire a weapon with my left
hand. However, as I previously showed you, when I demonstrated how you
ejected cartridge cases, all of those residues showed up, as well as,
I am sure, other foreign material that the paraffin removed from my
hands. And there were reactions on both hands, fronts and backs.
Now, theoretically, you should not find them on the backs over here,
because I had my left hand behind me, and you would find it on the
palm. We found reactions everywhere on the casts.
Representative FORD. It is 12:30 now. We will recess until 2 o'clock
this afternoon.
(Whereupon, at 12:30 p.m., the President's Commission recessed.)