Stringent controls placed on forensic evidence
There are many who argue the rules are too stringent and hamper crime investigations.
Under the Forensic Evidence Act, when a suspect is taken for questioning he can refuse to give what is described by one expert as an "intimate" sample, such as saliva, urine, blood or pubic hair.
Clothes, material under the nails and hair from the head can be taken without consent.
If a suspect agrees to provide a sample, consent must be given in writing. Even then the sample cannot be taken unless a range of procedures is followed, including obtaining approval from police brass a Superintendent or higher. If no charges are brought within six months, the sample is destroyed, although the deadline can be extended by the High Court.
As in the Phyllis Murphy murder, these rules do not apply to samples taken before introduction of the 1990 Forensic Evidence Act.
Britain has established a DNA database; those convicted of even minor crimes have to give samples.
Former head of the Forensic Science Laboratory, Dr Jim Donovan, supports such a database for Ireland.
"When Britain put 100,000 people on their database they ran 35,000 crime stains through, everything from blood left in a car to semen stains in a rape.
"They found 7,500 men guilty as a result, some of serious offences. There is a considerable value in having a database."
The idea is to discourage criminals who start off with small offences but eventually graduate to more serious ones.
But civil liberties groups have grave reservations.
Aisling Reidy, director of the Irish Council for Civil Liberties said: "The ICCL recognises that advances in DNA technology can prove invaluable to the gardaí in their investigation and detection of crime, and that the creation of a DNA database may seem like a desirable addition to crime detection resources.
"However, such a powerful tool brings with it inevitable and serious threats to privacy and potential for abuse and miscarriages of justice, which must be taken seriously and properly addressed."
She added it raises concerns about whose DNA information may be stored on the database, for how long, for what purpose, what safeguards protect the information and, significantly, what remedies for abuse will be available.
A European Council Resolution has suggested EU members consider "exchanging DNA analysis results."
But that's not possible until all member states operate DNA databases; there are no plans to introduce one here.
Professor Denis Cusack, head of forensic and legal science at UCD, said advances in DNA technology are valuable not to just help prove guilt but also to establish innocence.
