Perfect Murder, Perfect Town - Lawrence Schiller [324]
PCR (polymerase chain reaction) typing (also known as molecular Xeroxing) is a process in which tiny bits of DNA are replicated thousands of times to allow analysis and comparison. Once the DNA is amplified, it can be typed through genetic probes. While hundreds of genes can be examined, not all are suitable for forensic analysis. In the Ramsey case, the DQ-alpha and D1S80 genes were among those compared. The genes analyzed through PCR are not the same as those examined through RFLP testing, but PCR results can also yield ratios demonstrating that the likelihood of two people having the same combination of genetic markers is hundreds of millions to one.
** The greatest risk of contamination of DNA comes from other DNA samples. Material is collected with disposable tweezers by police officers and lab techicians, who are required to change gloves each time they pick up a sample. At a complex crime scene, an officer might use fifty or more pairs of gloves.
* A Colorado statute, C.R.S.16-3-309, generally authorizes the use of laboratory testing procedures by the prosecution, so long as procedures are in place to preserve possible exculpatory evidence (evidence that points to the possible innocence of a person). The statute hints, however, that “when a suspect has been identified or apprehended,” the suspect or his counsel may have a right to be present at destructive procedures that will not leave enough evidentiary material for later defense testing. The statute does not provide for a definition of “suspect” or explain what degree of suspicion is necessary before one is deemed to have been “identified.” Whiteside apparently took the view that a person was not a suspect until he had been named by police as such, charged or arrested in connection with a crime.
* The presence of facts or circumstances strong enough to produce a reasonable belief that the person charged with a crime is guilty. It does not indicate proof beyond a reasonable doubt but is enough to force the accused to stand trial. Also, in cases of search and seizure, it indicates the presence of sufficient evidence that the property subject to seizure is at a specified place.
** The level of certainty a juror needs in order to make a legal finding of guilt for a criminal defendant. This phrase is employed in jury instructions during a criminal trial, indicating that the defendant’s innocence is presumed unless the jury can see no reasonable doubt as to the guilt of the person charged. This standard does not require that proof be so convincing that no chance of error exists. It means that evidence must be conclusive enough that all reasonable doubt is removed from the mind of an ordinary person.
* There is no Colorado law mandating that the police department cooperate with the district attorney.
* Pete Hofstrom, who was present during the conversation with Patsy, was familiar with the Michael Manning case discussed on page 281. In that case the child’s mother, Elizabeth Manning, was told she would be treated “as a witness” rather than as a suspect. She then disclosed that her child was beaten to death by her companion. When she was prosecuted for murder, the Colorado courts held that because of what a deputy had promised, neither Manning’s disclosure nor anything the police learned from following up on it could be used as evidence against her. It is likely that the sheriff’s officers interviewing Patsy Ramsey assumed that what she told them on that occasion could never be used against her. That was probably wrong.
* Evidence that points to the possible innocence of a person.
* Hair has thirty-five characteristics, some of which are pigmentation, medulla, scales on the outside of hair, and the channel that runs through the center of each strand.
* The steps in DNA testing are as follows: Blood, semen, saliva, skin, or hair is labeled and shipped to a forensics lab. Only minute amounts—a single hair root, for example—are required. Then the sample is mixed with detergent and enzymes, which break open the cells and let out their DNA. The