Feb. 27 (Bloomberg) -- Mark Dixie and Steve Wright, both jailed in U.K. murder cases last week, have something else in common: the country's DNA database helped secure their convictions.

Dixie, who raped and murdered 18-year-old Sally Anne Bowman in south London, and Wright, who killed five prostitutes in Ipswich in December 2006, were both caught with samples taken when police arrested them for other offenses. Dixie took part in a bar brawl and Wright had stolen money from his employer.

The trials have reignited a debate about DNA profiling as a case challenging the practice is heard at the European Court of Human Rights. Opponents say storing genetic information breaches civil liberties and risks miscarriages of justice. The U.K. has built the world's biggest DNA database, with 4.2 million profiles, or seven percent of the population.

``It's good seeing all these people get caught after thinking they could get away with it,'' said Gillian Smith, 60, whose daughter's killer was traced by his DNA. ``How many more would they have killed if they hadn't picked them up?'' Smith said in a phone interview from her home in Yate, near Bristol.

Louise Smith, 18, was murdered on Christmas Day 1994. When police were forced to destroy 4,500 DNA samples after using them to help find Louise's murderer, Gillian and her husband Robert ran a successful campaign to change the law. From 2001, such profiles have been kept on a database.

From 2004, police in England, Wales and Northern Ireland are also allowed to take a DNA swab from people they arrest and keep the profile on the database, even if the person is released or acquitted by a court.

European Challenge

Lawyers for Michael Marper will argue today that because charges were dropped in a case of harassment against him, the police can't retain his sample under the European Convention on Human Rights. They will make the same case for a boy referred to just as ``S'' because he was 11 when arrested. He was acquitted from a charge of attempted robbery.

Peter Mahy, a lawyer for the challengers, says they want justice for people who haven't committed an offense.

``If you are not convicted of a crime you are entitled to be put back in the same position as anyone else without a criminal record,'' he said in a statement.

One solution would be to put the DNA of all U.K. residents and visitors on the database, Stephen Sedley, one of Britain's most senior judges, said last year.

``Everybody, guilty or innocent should expect their DNA to be on file for the absolutely rigorously restricted purpose of crime detection and prevention,'' said the judge, who heard the Marper case when it was appealed to the House of Lords, the U.K.'s highest court.

Dixie's Arrest

The introduction of a database with everyone's details on it would create a ``nation of suspects,'' the opposition Conservative Party says, and could undermine the principle that everyone is innocent until proven guilty. The U.K. database contains the records of hundreds of thousands of innocent people, including children, though it doesn't hold the details of every serious offender in the country, the party says.

Newspapers, Web sites and radio phone-ins in the U.K. have carried arguments by both sides. The Sunday Times headlined an opinion column with ``Leave our DNA alone'' while the Sunday Telegraph said ``We could not trust a national DNA database.''

Deoxyribonucleic acid, or DNA, is the genetic code found in every cell in the human body and is unique to each individual. Samples of saliva, blood, semen or sweat taken from crime scenes can be checked against DNA profiles to identify suspects.

Dixie could have been arrested within 24 hours with a database, rather than the nine months it took to track him down, Detective Stuart Cundy told reporters after his conviction.

`Back Door'

The U.K. isn't planning to set up a comprehensive database, according to Prime Minister Gordon Brown's spokesman, Michael Ellam. ``the prime minister is happy with the current position.'' In the European Union, 1.13 percent of the population's DNA records are on file. The figure is 0.5 percent in the U.S., according to the U.K. Parliamentary Office of Science and Technology.

Liberty, a London-based civil-liberties lobby group, opposes a U.K. national register and says a universal database shouldn't be introduced ``through the back door.''

``Taking the DNA of every man, woman and child is as expensive and impractical as it is dangerous,'' Shami Chakarbarti, director of the group, said in an e-mailed statement. ``It ignores the extremely intimate nature of DNA and the scope for error. We need a manageable database of those who've been convicted of sexual and violent crime.''

Gillian Smith disagrees. It took police 14 months to catch David Frost, the student who killed her daughter, even though his DNA was on her body. She wants everyone's DNA to be registered at birth.

``The biggest thing for the family is catching them. You need that, it helps,'' she said.

To contact the reporter on this story: Thomas Penny in London tpenny@bloomberg.net

Last Updated: February 27, 2008 07:39 EST