DNA

INTRODUCTION WHAT IS DNA? deoxyribonucleic acid no 2 people can have the same DNA, except identical twins. the chance of this kind of evidence being wrong is 1 in 10 million.

How is DNA obtained from a crime scene? blood Hair Semen Saliva bone (marrow) Flesh Urine teeth (pulp)

DNA AND THE LAW Issue: can the law keep up with technology? Can suspects be compelled to provide samples, and how those samples will be taken? Do you need a warrant? 4 th amendment – unreasonable search & seizure (history & today) Reasonable suspicion What crimes are considered under such a warrant?

Non-forensic applications recently used in Ottawa to identify 2 identical twins who had been adopted and accidentally separated at birth. Paternity cases Most powerful uses are in the CJ system

DNA in law enforcement In violent crimes, hair, blood and semen samples are more common than fingerprint evidence. true for sexual assault cases. investigations go much quicker. help implicate the guilty, would eliminate the innocent data base which could include all DNA of convicted sex/violent offenders

DNA in homicide cases could be used to help identify a murder weapon. For example, a knife with blood stains. used to distinguish "copy cat" crimes from serial crimes. connect crimes committed by the same offender, i.e. serial murders. determine if more than one offender was involved identify deceased/missing persons.

THE LEGAL QUESTIONS OF DNA EVIDENCE The legal question of taking a blood sample from an accused person who does not consent is a critical issue. Is it a form of self-incrimination, or does it constitute an unreasonable search? Consider a similar case: When people are pulled over on suspicion of impaired driving, they are required to give a sample of their breath. If the suspect refuses to give a sample, he/she can be charged.

Differences between drunk driving & homicide the more serious a crime is, the heavier the sentence and the greater the stigma. Therefore, the courts may be more stringent on the issues of constitutional rights.

Standard of proof Another issue in DNA search warrants is the determination of a standard or threshold of proof to justify the taking of a sample from an accused. The standard is usually “reasonable and probable” grounds. For example, an officer may see some erratic driving, smell alcohol on the suspect's breath, etc. But, DNA testing is more complicated, and may warrant a higher standard.

DNA vs. fingerprinting When people are arrested, they are required to undergo fingerprinting. is not an unwarranted invasion of privacy. SOME CANADIAN CASES: R. v. Alderton R. v. Legere

Getting the DNA sample the police have had to resort to some pretty imaginative means to try to get DNA samples from suspects obtaining a tissue that an individual has used to blow his nose and thrown away Retrieving shed hair Ryan Love case

INTERNATIONAL EXPERIENCE WITH DNA EVIDENCE ENGLAND In year old girl was raped and murdered. In July, 1986, second murder Richard Buckland confessed. DNA tests showed that the same man killed both girls, but Buckland was not that man The police asked the 5500 men in the area to give DNA sample. All gave samples except for a man named Colin Pitchfork

Florida V. Andrew The first case in the United States to use DNA the accused was convicted of over 20 cases of sexual assault or attempted sexual assault. There have even been cases where the accused requested a DNA test only to have it reveal his guilt.

POSSIBLE PROBLEMS WITH DNA EVIDENCE Critics of DNA worry that the police may over rely on DNA evidence. The following problems can arise with DNA evidence. Contamination problems: Heat, humidity, moisture, decomposition of a body, time since death, temperature where body was stored Sexual assault cases: the absence of semen does not mean that there was no sexual assault. great cost and time consumption.

DATABANKS The DNA of convicted sex offenders and other violent offenders could be stored into computers which would then be accessible to police forces could provide the ability to do split second searches and comparisons. would be similar in theory to the Automated Fingerprint I.D. System

Databanks will assist the police in 3 areas: 1. open cases 2. missing persons/unidentified deceased victims 3. convicted offenders

BUT….Civil liberty issues? what information will be stored? which offences require an offender to be in the computer? who will have access to the information, and for what purpose. ?

Need for DNA standards People v. Castro. The accused had murdered his neighbor and her 2 year old daughter. State of Minnesota v. Schwartz The accused was charged with the first degree murder of a stabbing victim.