The disappearance of a nine-year-old child in the eastern German city of Leipzig last week would usually have made local news, but this case sparked headlines in major newspapers and on television because the victim had been abused and murdered by a convicted sex offender and serial rapist who had spent several years in prison.

The victim, identified only as Mitja, didn't come home from school last Thursday and was last seen sitting next to his suspected murderer, 43-year-old Uwe Kolbig, in a tram in Leipzig, according to footage from video surveillance cameras.

Police in Leipzig discovered the child's corpse among the bushes on Kolbig's property. Kolbig, who is now in custody after attempting to commit suicide in Leipzig, allegedly sexually abused and then suffocated Mitja.

"Protecting children is top priority"

The case has triggered fury among politicians and the public alike who demand to know how a convicted sex offender could have been roaming freely in the city.

Markus Söder, Secretary General of the Bavarian-based Christian Social Union party demanded that pedophiles be locked away forever.

"Children are our most valuable resource, protecting them has top priority," Söder told Berlin daily Der Tagesspiegel. "That's why life-long preventive custody for pedophiles should become the norm."

Preventive custody, aimed at stemming further crimes, was first introduced in Germany in 1933. It only applies to repeat offenders and is an add-on to the prison sentence that forces criminals to remain in prison until they are no longer deemed a danger to society.

Preventive custody for dangerous criminals has become the rallying point of a growing debate in Germany on children's safety fuelled by a spate of highly-publicized cases in recent years, many of them involving rape and sexual abuse, in which minors have been the victims of repeat sex offenders.

Widening the law?

In 2005, a nine-year-old boy in Bavaria was molested and strangled to death by a recently released child murderer, Martin Prinz. When he was 18, Prinz had been convicted for stabbing an 11-year-old to death after attempting to rape him. The suspect in the current Leipzig case, Kolbig, was 17 years old when first sentenced for sexually abusing children.

Under German law, preventive custody currently only applies to criminals over 21.

German Justice Minister Brigitte Zypries this week, however, indicated she may expand the law to cover younger criminals who are sentenced to a minimum of seven years for serious offenses.

That would mean dangerous criminals, including sex offenders and murderers, who committed crimes before they turned 21, could then be treated as adult criminals. Psychologists would evaluate their cases every year to determine if they pose a threat to society. That means thereotically they could even be locked away indefinitely.

Controversial proposal

The proposal is controversial and has deeply divided opinion. Advocates say the measure would protect citizens from some of society's worst offenders who fail to reform after long prison sentences and therapy.

"The move is long overdue and is particularly crucial when it comes to sex offenders," said Georg Ehrmann, chairman of the board of Deutsche Kinderhilfe Direkt, a charity that works for ill and disadvantaged children. "Studies have shown that those who commit sex offences at a young age suffer psychological damage that lasts a lifetime. So their drive for sex crimes only gets worse with age."

However, those familiar with the law's reach argue that the measure would be catastrophic and rob young criminals of any chance of reintegrating back into society.

Stefan Caspari, a judge and a member of the Deutscher Richterbund, an association of lawyers and judges, said that though there were occasional cases of relapses among released criminals, the solution could not lie in simply locking away people based on assessments by experts.

"We're talking here about young people who are still in a developing phase of their lives," Caspari said. He pointed out that much of the current preventive custody in Germany is already used for sex offenders widely considered difficult to treat.

Sex offender worked at a school

Both sides agree that the government also needs to close certain loopholes in the legal system if it is to lower the risk of repeat sex offenses.

News that Kolbig worked at a zoo in a school in the state of Saxony in 2001 and 2002 despite multiple convictions for child sexual abuse is a scandal, Ehrmann said.

He added that German data protection laws don't allow employers to check personal records of their employees for prior sex offense convictions for before hiring them for jobs involving working with children.

Another area in need of reform is the hiring of qualified psychologists to evaluate criminals before releasing them, Caspari said.

"We definitely need more well-trained experts who are both well-experienced in dealing with sex offenders as well as have the self-confidence and responsibility to make crucial decisions about criminals which may or may not always be right," he said. "We have to remember that these experts are human after all."

Ehrmann, however, pointed out how costly human errors could sometimes turn out.

"Last year an inexperienced 29-year-old psychologist spent just 45 minutes reviewing the case of Mario M, a convicted sex offender, and decided he didn't pose a danger," Ehrmann said. "Look where that led to."

The freed Mario M kidnapped a 13-year-old girl in the eastern city of Dresden, held her captive in his apartment for five weeks and repeatedly raped her before she was able to escape.