Instruction Bank # I-868 (Re: F 2.80 n8 [Expert Witnesses: DNA Jury Instructions And Motions].)
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PEOPLE V. O.J. SIMPSON (1995), LOS ANGELES SUPERIOR COURT NO. BA 097211
PROPOSED INSTRUCTION ON DNA STATISTICS
You are about to be presented DNA evidence which includes statistical estimates of how rare or common DNA banding patterns are in various populations. You may consider these statistical estimates in evaluating the liklihood that different people would coincidentally have the same DNA banding patterns.
On the other hand, these frequency statistics are not an estimate of the liklihood of a false or misleading match of DNA banding patterns due to errors in the collection and handling of samples, errors in laboratory analyses, or intentional tampering with the samples.
The liklihood of a coincidental match between people who happen to share the same DNA banding pattern is a separate and independent issue from the liklihood of a false or misleading match due to errors in the collection and handling of samples, errors in laboratory analyses, or intentional tampering.
In the end, you will need to consider all the evidence in this case when evaluating the weight of the DNA evidence.
D1 Cal. Evid. Code Section 4.03(c); People v. Riser (1956) 47 Cal.2d 566, 580-81; Robinson vs. Commonwealth (1971) 183 S.E. 2d 179, 180 (Va. Sup. Ct.)
Evidence of the analysis of blood or hairs or fibers or similar evidence recovered from a crime scene may not be considered until you first determine the evidence was preserved in an unaltered and unchanged condition from the time of its seizure at a crime scene until the time it was analyzed. This requirement, the purpose of which is to prevent contamination of or tampering with evidence, is known as the “chain of custody” requirement. Only if you determine that a reasonable chain of custody was accounted for may you then consider the results of any analysis or testing of such evidence. If you determine that a reasonable chain of custody of such evidence was not established, however, you must disregard such evidence and not consider it for any purpose.
D2 Cal. Evid. Code Section 4.03(c): “If the court admit the proffered evidence under this section, the Court . . . on request shall . .. instruct the jury to determine whether the preliminary fact exists and to disregard the proffered evidence unless the jury finds the preliminary fact does exist.”
Evidence of the comparison of blood drops allegedly found on the walkways and driveways of the Bundy crime scene with a blood sample provided by Mr. Simpson has been introduced for the purpose of showing the identity of the perpetrator of the murders. Before you may even consider such evidence, you must first determine whether the blood drops allegedly found at the crime scene were deposited by the perpetrator of the murders on June 12, 1994. If you determine this fact to be true, such evidence may then be considered by you for the purpose of determining whether it tends to show the identity of the perpetrator of the murders. If you determine that the alleged blood drops may have been deposited at some other time, however, you must disregard this evidence and not consider it for any purpose.
D3 Cal. Evid.. Code Section 4.03(c): “If the court admits the proffered evidence under this section, the Court on request shall . . . instruct the jury to determine whether the preliminary fact exists and to disregard the proffered evidence unless the jury finds that the preliminary fact does exist.”
Evidence of the comparison of blood which was not discovered on the back gate at the Bundy crime scene until July 3, 1994, and of blood which was not discovered on a sock allegedly found in Mr. Simpson’s bedroom until August 4, 1995 with a blood sample provided by Mr. Simpson and a blood sample recovered from the body of Nicole Brown Simpson has been introduced for the purpose of showing the identity of the perpetrator of the murders. Before you may even consider such evidence, you must first determine whether the blood found on the back gate and the sock was deposited by the perpetrator or victim of the murders on June 12, 1994. If you determine such fact to be true, such evidence may then be considered by you for the purpose of determining whether it tends to show the identity of the perpetrator of the murders. If you determine that blood may have been deposited on the back gate or socks at some time subsequent to June 12, 1994, however, you must disregard this evidence and not consider it for any purpose.
D4 Cal. Evid. Code Section 4.03(c): “If the court admit the proffered evidence under this section, the court . . . on request shall . . . instruct the jury to determine whether the preliminary fact exists and to disregard the proffered evidence unless the jury finds that the preliminary fact does exist.”
Evidence of the comparison of blood allegedly found in the Bronco automobile and at Mr. Simpson’s Rockingham residence with a blood sample provided by Mr. Simpson and blood samples recovered from the bodies of the victims has been introduced for the purpose of showing the identity of the perpetrator of the murders. Before you may even consider such evidence, you must first determine whether the blood allegedly found in the Bronco or at the Rockingham residence was deposited after the murders, on June 12, 1994. If you determine this fact to be true, such evidence may then be considered by you for the limited purpose of determining whether it tends to show the identity of the perpetrator of the murderers. If you determine that the blood allegedly found in the Bronco or at the Rockingham residence may have been deposited at some other time, however, you must disregard this evidence and not consider it for any purpose.
D5 Cal. Evid. Code Section 4.03(c): “If the court admits the proffered evidence under this section, the Court . . . on request shall . . . instruct the jury to determine whether the preliminary fact exists and to disregard the proffered evidence unless the jury finds that the preliminary fact does exist.”
Evidence of the comparison of hairs and fibers allegedly found on various items at the Bundy Crime scene with hair samples provided by Mr. Simpson and fibers removed from the Bronco automobile has been introduced for the purpose of showing the identity of the perpetrator of the murders. Before you may even consider such evidence, you must determine whether the hairs and fibers allegedly found on various items were deposited by the perpetrator of the murders on June 12, 1994. If you determine this fact to be true, such evidence may then be considered by you for the limited purpose of determining whether it tends to show the identity of the perpetrator or the murders. If you determine that the hairs and fibers allegedly found on various items may have been deposited at some other time or may have been transferred from some item where they were deposited at some other time, you must disregard such evidence and not consider it for any purpose.
D6 Cal.Penal Code, Section 1127b; People vs. Morris (1988) 199 Cal.App.3d 377, 391;People vs. Lindsey (1978) 84 Cal.App.3d 851, 866.
In describing the comparison of hairs and fibers in this case, the witness was not permitted to use the word “match.” When a witness offers an opinion that two hairs or fibers bear similar characteristics, it does not necessarily mean that they came from the same source. The jury alone has the final responsibility to decide the weight to be given to testimony regarding similarities in hairs and fibers. Such evidence alone is insufficient in the absence of other corroboration to identify the defendant as the perpetrator of the offenses charged.
D7 State vs. Bloom (1994) 516 N.W. 2d 159, 171 (Minn. Supreme Court, Page, J. concurring)
A given DNA profile may be shared by two or more people. The random match probability statistic used by DNA experts is not the equivalent of a statistic that tells you the likelihood of whether a defendant committed the crime. The random match probability statistic is the likelihood that a random person in the population would match the characteristics that were found in the crime scene evidence and in the defendant’s DNA. Such probability statistics assume that there has been no contamination of the DNA samples and no errors in the laboratory analysis.
D8 Cal.Penal. Code Section 1127(b); State vs. Bloom (1994) 516 N.W. 2d 159, 171 (Minn. Supreme Court, Page, J., concurring).
Where a witness offers an opinion that the DNA profiles of two blood samples “match” it does not necessarily mean that they came from the same source. The jury alone has the final responsibility to decide the weight to be given to testimony regarding DNA “matches.”
D9 People v. Chandler (1971) 17 Cal.App. 798; Evidence Code Sections 412 and 413.
PROPOSED PINPOINT INSTRUCTIONS ON DNA STATISTICS – PEOPLE V. ASSAD MUHAMMAD, (2001) SOLANO COUNTY SUPERIOR COURT, NO. 142576
INSTRUCTION NUMBER 1
You have been presented DNA evidence which includes statistical estimates of how rare or common DNA banding patterns are in various populations. You may consider these statistical estimates in evaluating the liklihood that different people would coincidentally have the same DNA banding patterns.
On the other hand, these frequency statistics are not an estimate of the liklihood of a false or misleading match of DNA banding patterns due to errors in the collection and handling of samples, errors in laboratory analyses, or intentional tampering with the samples.
The liklihood of a coincidental match between people who happen to share the same DNA banding pattern is a separate and independent issue from the liklihood of a false or misleading match due to errors in the collection and handling of samples, errors in laboratory analyses, or intentional tampering.
In the end, you will need to consider all the evidence in this case when evaluating the weight of the DNA evidence.
INSTRUCTION NUMBER 2
You have heard testimony about frequency estimates calculated for matches between known reference blood samples and DNA evidence from item 37A, the pantihose. The random match probability statistic used by dna experts is not the equivalent of a statistic that tells you the likelihood of whether the defendant committed these crimes. The random match probability statistic is the likelihood that a random person in the population would match the characteristics that were found in the crime scene evidence and in the reference sample. These frequency estimates are being presented for the limited purpose of assisting you in determining what significance to attach to the DNA evidence.
INSTRUCTION NUMBER 3
A given DNA profile may be shared by two or more people. The random match probability statistic used by DNA experts is not the equivalent of a statistic that tells you the likelihood of whether a defendant committed the crime. The random match probability statistic is the likelihood that a random person in the population would match the characteristics that were found in the crime scene evidence and in the defendant’s DNA. Such probability statistics assume that there has been no contamination of the DNA samples and no errors in the laboratory analysis.
PROPOSED PINPOINT INSTRUCTION ON EXPERT TESTIMONY PEOPLE V. DONALD BOWCUTT (2000), SISKIYOU SUPERIOR COURT NO. 95-707
Evidence has been presented concerning physical evidence such as DNA evidence, hair and fiber evidence and experts’ opinions concerning the analysis of such physical evidence. You are the sole judges of whether any such evidence has a tendency in reason to prove any fact at issue in this case. You should carefully review and consider all the circumstances surrounding each item of evidence , including but not limited to its discovery, collection, storage and analysis. If you determine any item of evidence does not have a tendency in reason to prove any element of the crimes charged or the identity of the perpetrator of the crimes charged, you must disregard such evidence .
SPECIAL JURY INSTRUCTION 1
To evaluate evidence of a DNA inclusion, you must consider the possibility of a coincidental inclusion between two different persons who happen to have the same genetic characteristics. To help you evaluate this possibility, you have been given statistical estimates of the frequency of the inclusion characteristics in various populations as well as the error rate for DNA testing.
You may rely on these statistical estimates to help you evaluate how rare or common the inclusion may be. The statistical estimates do not however, indicate the likelihood that two similar samples are or are not from the same person.
You must consider all of the evidence in this case, not just the DNA evidence, when evaluating the likelihood that samples that are similar on a DNA test are, or are not, from the same person.
The burden is on the government to prove beyond a reasonable doubt that the defendant is the person who committed the crimes with which he is charged.
If after considering the circumstances of the DNA evidence and any other evidence in the case, you have a reasonable doubt wether the defendant was the person who committed the crime, you must give the defendant the benefit of that doubt and find him not guilty.
SPECIAL INSTRUCTION 2
DNA evidence and testimony regarding DNA evidence has been received in this trial for the purpose of identifying the defendant as the perpetrator of the crime charged. In determining the weight to be DNA evidence, you should consider the reliability of the evidence as well as other factors which bear upon the accuracy of the DNA evidence, including but not limited to any of the following:
The validity and reliability of the test methods used;
The accuracy and reproducibility of the test results;
The risk of contamination;
The extent to which the defendant either fits or does not fit the genetic profile of the evidence;
The validity and reliability of the database used to calculate the estimated frequency of a genetic profile;
The risk of a false positive or false negative result based on the laboratory error; and
Any other evidence relating to the DNA evidence and its ability to link or not link the defendant to the charged crime.
[Given in People v. Bowcutt (2000) Siskiyou Superior Court # 95-707.]
