Professor MacDonell, would you please tell the ladies and gentlemen of the jury how is it that you are familiar with the drying times of bloodstains under various conditions?
The institutes that I began directing in 1973, of which there have now been 43, have an experiment where we do drying times of blood in fabric, on wood, glass, various surfaces. This is done in small volumes and in large volumes and also with many fabrics. This is a routine experiment that has been done for many years. The amount of time required is such that for the larger pools of blood, we can't do that in a single day, so that was deleted from the fourth publication. We still do, in experiments 12 and 13, some of the blood that is spread out to see how rapidly it will dry, put on clothing, particularly fabrics that are difficult, like arnel and nylon combinations that appear to be stained on one side, in fact they were stained on the other, so we are aware that there are very dangerous areas in looking at a sample of material and drying to identify which side was stained, without doing the actual experiment, see we do this routinely. I have done it on I don't know how many cases. I would say perhaps a hundred, 200, 300 cases where fabrics are involved we will usually test the actual fabric to determine transfer characteristics and drying time, and that is how I am familiar with it.
And sir, based on those demonstrations and experiments that were conducted routinely in the institutes by your students that you just described, does the volume of blood on an object affect the drying time?
Well, the more blood there is, the longer it is going to take to dry, given the same surface area. A pool of blood that is contained, for example, in a bowl, is going to take much longer than the same area, but a very thin film.
And sir, did you estimate the approximate volume of blood that originally existed on that stain on the ankle in 13-a, sock 13-a?
Yes. I estimated the volume to be approximately one drop. It is not soaked through on the periphery. Those are the pictures we have seen, 1276 I believe or 1277, excuse me, that shows the blood on the surface, at least on the periphery. The center has been cut out and it would have been slightly heavier, so that stain could be caused on that material, I would estimate with a--just one drop, 50 microliters, perhaps slightly more or slightly less, but I would estimate one drop would be adequate.
KEY QUOTENow, you said that the drying time is affected by the volume of blood. Is it also affected by the type of surface that the blood is drying on?
For instance, does it make a difference whether it is drying on fabric as opposed to a glass table?
Yes. The--the fabric would act as a wick, so to speak, up to a certain point, and would allow the blood to dry more rapidly, but if it is a thick fabric, it would act as a reservoir and it would contain the blood and reduce the surface area, so it would dry slower. Blood spreads out on a surface, just a table top or anything, if it is a thin film will dry very rapidly. If it is a small spatter, a small two-millimeter to one-millimeter diameter spot, it will dry very quickly. Within a matter of a minute you can just wipe across it and it will be dry. It depends a great deal on the surface.
Sir, even within the--that subcategory of surfaces which we will call textiles or fabrics, will there be variation in the drying time between different types of fabrics?
Yes. We conducted experiments of that type to present a paper to the American Academy of Forensic Science some years ago dealing with the effect of enzymes in detergents. Several years ago there was tide x and all of these little bugs chewing up the stains.
What I'm asking, sir, is not so much the chemicals that the item might have been treated with, but is there difference in drying times, for instance, between synthetics and natural fibers?
And all things being equal, given the other factors, what is the difference in drying between, let's say, a synthetic, which the sock is in this case, and cotton?
If you have a synthetic fiber, it is non-porous. It does not itself soak in a fluid. Notwithstanding, the fluid will soak in by capillary action or just a wetting between the individual fibers, but a natural fiber, such as cotton, ramey, hemp, jute, some of these thing are porous. Wool, for example, is porous. Animal fibers are porous, but not to the extent of the natural fibers, so therein you have soaking, not into the weave, but also into the individual fibers, and again that--that retards the evaporation or the drying time, above and beyond synthetics where the blood is exposed, although in between some of the fibers which do not absorb blood.
If I was to try and distill that at least for myself, professor, would that mean that all other things being equal that blood will dry more rapidly on a synthetic fiber than on a cotton fiber?
And sir, is there a difference in drying time for blood if it is dabbed or smeared on a surface versus blood that has simply fallen onto a surface or dripped onto a surface?
Well, if the dripping blood actually penetrates the fiber and goes down into the fiber, it wets it, in other words, that will dry much more slowly than if you just have it on the surface where there is--air can actually get underneath it through the fiber.
I believe you testified, sir, that in your opinion in this case the bloodstain found on ankle 13 is a result of a dabbing of the surface, as opposed to blood simply dripping or spattering onto the surface?
Is it your testimony, sir, in this case, based on your observations of the ankle stain, that the blood did not spatter onto the ankle area of sock 13-a?
Is it your testimony, sir, that the blood got there by being--by being the result of some kind of compression, some object brought to bear on the sock, and that object had blood on it?
Now, sir, in addition to those factors which you have already described, is there a difference between the time needed to air dry a bloodstain versus when the stain is on material that is actually in contact with a living body, such as a sock pressed up against an ankle?
Could you explain to the jury what affect it has on drying time for the item of clothing which has the blood to be in contact with the living human body, as opposed to when it is air dried?
Sir, have you compared in the past, prior to your involvement in this case, the different times in which an identical bloodstain will dry if it is air dried as opposed to being in contact with a human body--with material that is in contact with a human body?
Yes. Over the course of many years I have conducted experiments where fabric was actually placed on a person's arm or leg and blood was impregnated into that material. The drying time and the soaking through characteristics were the object of doing that experiment. I can cite at least one case where we did that using identical twins so the blood groups would be identical.
--based on your expertise, does blood dry faster or slower when it is on material that is in contact with a person's skin when the person is living, as opposed to when it is simply air drying and not in contact?
All things being--based on your experiments--I'm sorry. Based on your studies and experiments, even prior to your involvement in this case, all other variables being equal, is there a difference between the drying time of blood on a fabric that is simply in the air drying as opposed to blood on a fabric which is in contact with a living body?
Have you done experiments to answer that particular question, prior to your involvement in this case?
Could you please describe what experiments you've done of that nature where you would actually compare the drying time where all the other variables are identical except for the one variable being the fabric is against the skin of a living person, as opposed to the fabric not being against the skin of a living person?
Yes. We have done experiments, as I stated, to determine both the drying time on a person and drying time of that fabric in air, and because living people are warmer than the environment, with the exception of some of the weather lately, you will have blood drying on the garment much more rapidly.
KEY QUOTEOverruled. I mean sustained. The answer is stricken. The jury is to completely disregard that last answer. Proceed.
Professor, have you done any of these drying experiments on socks prior to this case in synthetic socks?
KEY QUOTEAnd have those experiments done on shear synthetics that are light and shear like the socks been done where one part of the fabric is in contact with the body picking up the body heat and the other fabric is simply air drying?
And based upon those experiments, sir, what is your expert opinion as to which will dry faster?
Your Honor, the Prosecution has entered into a stipulation with regard to the next exhibit which shall be--
--which is the official records of the U.S. weather service, national weather service at Los Angeles airport for June 12th and June 13th.
Have you had a chance to examine the national weather service statistics for Los Angeles airport for the evening of June 12th and the morning of June 13th, 1994?
Okay. And first of all, can you tell us, sir, what was the temperature range between approximately ten o'clock in the evening on June 12th, 1994, and 9:30 the morning of June 13th, the approximate--June 13th?
The temperature range was between 63 degrees Fahrenheit and 66 degrees Fahrenheit, according to the document I have.
And during that same period of time, sir, when you said the temperature range was between 63 and 66 degrees, does it also state what the dew point was?
And during that same period of time, sir, is there any indication from the official national weather service printout here that there was any dew on the ground on the night of June 12th into the early morning hours of June 13th?
Well, it indicates that the temperature--the dew point range was below the temperature range all the times, so there would have been no dew formation.
Could you please say, sir, what was the closest the dew point ever got to the temperature during that twelve-hour period?
Wait, wait, wait, wait. You are having this witness testify to atmospheric conditions during the course of the--
This is beyond what he is qualified to testify to at this point, so the objection is sustained.
You said that the temperature between those hours of approximately ten o'clock on the evening of the 12th and 9:00, 9:30 the next day, were between 63 and 66 degrees; is that correct?
Are you familiar, through your studies, sir, on what the surface body temperature of a person is?
It is below the temperature of blood which is 100 degrees. Body temperature is 98.6. I think the surface temperature is several degrees below that, depending upon the environment. If it is a very cold day, your skin will be cooler than on a hot day. I think that is common sense.
To your knowledge, sir, and based on your experience, will the body temperature of a living personal be greater than 63 degrees Fahrenheit?
Sustained. Excuse me, professor. If there is an objection being made, don't answer.
By the way, while you have those certified records in front of you, sir, are you aware of the fact that when Dr. Lakshmanan of the medical examiner's office testified he said that on June 13th at about 1:46 P.M. the temperature was 64 degrees, page 32052 of the transcript, was Dr. Lakshmanan correct or incorrect when he gave that testimony?
Ladies and gentlemen, we are going to take our recess for the lunch hour. Please remember all my admonitions to you. Don't discuss the case among yourselves, don't form any opinions about the case, don't conduct any deliberations--don't conduct any deliberations until the matter has been submitted to you, do not allow anybody to communicate with you with regard to the case. Stay healthy. See you at one o'clock.
I estimated the volume to be approximately one drop. It is not soaked through on the periphery... that stain could be caused on that material, I would estimate with a--just one drop, 50 microliters, perhaps slightly more or slightly less, but I would estimate one drop would be adequate.
Yes. We have done experiments, as I stated, to determine both the drying time on a person and drying time of that fabric in air, and because living people are warmer than the environment, with the exception of some of the weather lately, you will have blood drying on the garment much more rapidly.
Professor, have you done any of these drying experiments on socks prior to this case in synthetic socks?
It is unless freezing.