New guidelines issued to collect, store DNA samples
NEWDELHI: The Delhi government and Delhi police have drafted guidelines for collecting forensic samples at hospitals and crime scenes to prevent contamination and putrefaction and fast-track analysis at the city’s only forensic science laboratory.
The guidelines were drafted on the Delhi high court’s directions in April this year.
The court had found lapses at every stage: from collection of samples to storing and delivery to the forensic laboratory.
The court direction was one in a series of orders in a bail plea where examination of important witnesses could not be conducted because of a pending forensic report.
The new guidelines specify how to collect various biological samples such as blood, urine, semen and tissues.
“Though some standards were in place, they were not being followed. After these guidelines are presented to the court, it will have a judicial stamp and would have to be followed,” said OP Mishra, additional director, Delhi government’s department of home.
The guidelines are to be presented on the next hearing date in August.
Nearly 50% biological samples get putrefied before they are filed with the forensic laboratory, according to an affidavit filed by the state.
Even after the samples are filed, it takes between two to four years for the lab to analyse them and present a report, say Delhi government doctors.
For example, blood samples can be collected on gauze, dried, and stored in a paper envelope or liquid blood can be stored in a vial either at the crime scene by a police officer or during the registration of a medico-legal case or post-mortem by the doctor.
Clothes with blood stains or semen must be air-dried at room temperature and packed in a paper envelope or cloth parcel, the guidelines say.
“Putrefaction is one of the biggest problems. Air-drying can preserve these samples for years, but when they aren’t dried properly before storing, they can get spoiled. Storing them without drying in plastic containers or polythene bags that are completely air tight leads to the growth of anaerobic bacteria,” said Dr Deepa Verma, director of Delhi’s forensic science laboratory.
The Delhi government has asked its hospitals to conduct regular workshops to ensure the guidelines are followed.
“The guidelines will streamline and hasten the process. In cases where the samples putrefy, DNA can be extracted but it is not as clear and takes longer to
Should be collected in glass containers and properly packed in wooden boxes
Strict guidelines about preservation of samples
All exhibits should be kept at 4°C
analyse. We can ask for another sample but sometimes the evidence is lost,” said Dr Verma.
When taking hair from a victim or the accused, the samples must be taken from the root. If the hair is collected from the crime scene, the officer must collect as much hair and keep it in a paper packet, the guidelines say. (See box)
While the guidelines were being prepared, the court had directed the commissioner of police to ensure all malkhanas at all police stations have proper cold storage facilities.
The court had also asked the health secretary to ensure the material for packaging and sealing samples are available in all hospitals.