The Evidence in Court how evidence is received in a court of law is extremely – important to a crime scene professional. Because of the view of Constitution’s and the rights of the accused, it is crucial that those “innocent until proven guilty” in law enforcement understand the types of evidence, how it is perceived in court, how to testify to its significance, and the importance of proper evidence collection and handling Power of the Evidence in Court Probative Value Higher value if the evidence can prove something in court The lower the probability of an event, the higher the probative value Probability the frequency of the occurrence of an event a) – Defines the odds that a certain event will occur (or the matching of a certain pieces of evidence) Normally found by multiplying the odds Example if a coin is flipped 100 times and comes up heads – 50 times, the probability of coming up heads is 50 out of 100, or 5 out of 10 Product Rule calculate the overall frequency of occurrence of in – a population Example the OJ Simpson case: Blood factors from a crime – scene that match OJ’s blood (Bertino, 2009) Product Rule 26 x .85 x .02 = .0044 or 0.44%, or less than 1 – out of 200 people would be expected to have this combination of blood factors Types of Evidence in Court Direct Evidence evidence that establishes a fact – Eyewitness testimony or testimony victim’s Confessions Physical evidence found on a person Audio or visual recording of the act or crime Indirect Evidence Circumstantial evidence Requires that a judge and/or jury make inferences about what transpired at the scene of a crime Not definitive proof
The Evidence in Court – how evidence is received in a court of law is extremely important to a crime scene professional. Because of the Constitution’s view of “innocent until proven guilty” and the rights of the accused, it is crucial that those in law enforcement understand the types of evidence, how it is perceived in court, how to testify to its significance, and the importance of proper evidence collection and handling Power of the Evidence in Court Probative Value Higher value if the evidence can prove something in court The lower the probability of an event, the higher the probative value Probability – the frequency of the occurrence of an event a) Defines the odds that a certain event will occur (or the matching of a certain pieces of evidence) Normally found by multiplying the odds Example – if a coin is flipped 100 times and comes up heads 50 times, the probability of coming up heads is 50 out of 100, or 5 out of 10 Product Rule – calculate the overall frequency of occurrence of in a population Example – the OJ Simpson case: Blood factors from a crime scene that match OJ’s blood (Bertino, 2009) Product Rule – 26 x .85 x .02 = .0044 or 0.44%, or less than 1 out of 200 people would be expected to have this combination of blood factors Types of Evidence in Court Direct Evidence – evidence that establishes a fact Eyewitness testimony or victim’s testimony Confessions Physical evidence found on a person Audio or visual recording of the act or crime Indirect Evidence Circumstantial evidence Requires that a judge and/or jury make inferences about what transpired at the scene of a crime Not definitive proof