Why Identical Twins Are a Nightmare for the Legal System

This article originally appeared on VICE Germany

In the early hours of the 25th of February, 2009, three masked men broke into Kaufhaus Des Westens, a luxury department store in Berlin. Surveillance cameras showed them sliding down ropes from the roof, before raiding cabinets and display cases filled with jewellery. The men escaped with around €5 million worth of goods. It was the stuff movies are made of – Spiegel International called it: “Germany’s most spectacular heist in years.”

For the police, it should have been a cut-and-dried case. They had reams of surveillance footage and found a latex glove at the scene; later forensic analysis revealed it contained a trace of DNA from a single drop of sweat. But when they ran it through their criminal database, the result led them up an unexpected path. There wasn’t just one result, there were two: 27-year-old identical twins, Hassan and Abbas O. This raised a problem – one that has always been a problem in other investigations around the world.

German law stipulated that all criminals must be individually proven guilty, but the DNA sample could not distinguish between Hassan and Abbas. Fraternal twins are two people born from two different eggs in the same pregnancy. But identical twins, scientifically known as monozygotic twins, are born when a single egg is fertilised to form one zygote, which then splits into two separate embryos. This means the DNA in identical twins is a near-perfect mirror when it comes to standard DNA tests.

From the evidence they had, German authorities could prove that at least one of the brothers had taken part in the robbery, but they couldn’t establish which one without reasonable doubt. Even a motion profile, created from surveillance footage, couldn’t convict either man. Before the case could even go to trial, the twins were released. "We have bitten our teeth – the process is dead," said Chief Prosecutor Sjors Kamstra to German news agency dpa International.

The situation has changed since 2009. There are now advanced methods that can find tiny differences in DNA between identical twins, based on unique genetic mutations. Bad news for any identical brothers and sisters planning the heist of the century. But these procedures are extremely expensive – investigators have to weigh up each case and judge whether the public interest justifies the financial expense.

When it comes to smaller crimes, like speeding or stolen credit cards, identical twins are still causing judicial nightmares. As recently as 2016, The Independent reported that a British man was cleared of dangerous driving after he accused his twin brother of being the one driving at the time. Again, both visual and DNA evidence proved inconclusive. “We have bottomed out every nook and cranny,” the prosecutor said of the case.

"We represent a pair of twins in our office,” says Berlin criminal defence attorney, Carsten R. Hoenig. “It is always a great pleasure to defend them from fines." Hoenig’s process is simple: once the police are sure they have the right person after comparing visual evidence (for example, speed camera footage) with a passport photo, Hoenig says he will “send another passport photo, of the twin brother, and ask if it could have been him, too".

Quite often, Hoenig explains, it is no longer possible to determine the culprit without reasonable doubt, and the process must be stopped. He has readymade text templates with the respective passport photos for his twin clients.

"As a close relative, you don't have to testify at the expense of your brother. And you don't have to incriminate yourself,” says Hoenig. In other words: all that matters is that the twins don’t testify against each other and stay quiet. All you have to do in court is give your name, age, place of residence and profession. Apart from that, the public prosecutor's office has the burden of proof. The accused doesn’t have to prove his innocence, and neither do twins. "If the twins stay silent when defending themselves and there is no other strong evidence, then it's over," says Hoenig.

The expensive DNA analysis for high profile cases came too late to catch Berlin robbers Hassan and Abbas. The statute of limitations for their case expired last year without any fresh evidence being brought to trial, and the €5 million worth of stolen goods was never recovered. "We are proud of the German legal system, and grateful," the brothers told Der Tagesspiegel after their case was dropped.