Officials in New York have been looking into whether DNA tests to find relatives of suspects could help them crack unsolved crimes.

The American state has been looking into whether to allow familial DNA testing as part of criminal investigations. This technique has been used in the investigation of violent crimes in the UK since 2002 and involves running DNA samples found at crime scenes into a database of offenders to find similar profiles, which could belong to biological relations of the person responsible.

However, as the method involves people who are innocent of the crime being investigated, it is considered to be highly controversial, although it has already been adopted by 10 other US states, including Florida, California and Texas. And the Commission on Forensic Science in the state of New York wants more consultation to be carried out before the process is used by police looking at cold cases.

One of the investigations that people believe could benefit from familial DNA testing being approved by the state is the unsolved murder of Karina Vetrano, a 30-year-old woman who was attacked and strangled in August as she went jogging in a park in Queens.

Investigators managed to collect a DNA sample from her body but have been unable to find a match on either the state or national law enforcement databases. NYPD detectives now believe that the next logical step would be to look for partial matches to see if they can find someone who could be related to Karina’s killer.

Karina’s mother, Cathy, said: “Our only goal in life is to find out who did this to our daughter. So if there’s any method available to do that, we want it done.”

Fears about privacy

However, opponents say the technique could infringe on people’s privacy and other civil liberties.

Donna Lieberman, the executive director of New York Civil Liberties Union’s, said: “A policy that implicates New Yorkers in a criminal investigation solely because they are related to someone with DNA in the state’s databank is a miscarriage of justice.”

The first case ever to be solved through familial DNA testing was the murder of three 16-year-old girls in woods near Port Talbot in South Wales in 1973. For many years the identity of the person who killed Pauline Floyd, Geraldine Hughes and Sandra Newton remained a mystery for many years.

In 2000, Dr Jonathan Whitaker, a forensic scientist, reviewed the cold case and managed to produce a full genetic profile from DNA samples taken from the victims but couldn’t find a match on the UK database. In October 2001, Dr Whitaker decided to try another approach and look for partial matches and uncovered one, a man called Paul Kappen.

Further investigation revealed that Paul’s father, Joseph Kappen, had been interviewed as a suspect by officers investigating the murders. However, Joseph had already died of lung cancer in 1990 so police officers had to get permission from his family to exhume his body for DNA testing.

This was carried out in May 2002 when DNA from Joseph’s teeth and femur was found to match the profile discovered on the three victims.

The similarity in DNA between two people who are biologically related allow people to find out whether they are related through relationship DNA tests. As well as paternity and maternity tests, laboratory staff can also determine whether two people are related in another way, for example being siblings.

AlphaBiolabs offers the fastest DNA testing in the world both for members of the public and official organisations such as the Child Support Agency, the UK Border Agency, local authorities and courts.