MICHAEL GOTTSCHALK/AFP/Getty A police officer on a motorbike drives past the main entrance to Berlin's iconic Kaufhaus des Westens department store

Related The Annual Twins Days Festival

It's an idea beloved by screenwriters: the perfect crime. But in Hollywood movies, even the cleverest plot is usually derailed by an unforeseen hitch. Now a real-life heist in Germany seems to have flouted that rule along with its moral subtext that crime doesn't pay. In January, $6.8 million worth of jewelry was snatched from the cases of Kaufhaus des Westens, a luxurious seven-story department store universally known as KaDeWe and as much a Berlin landmark as the Victory Column and the Brandenburg Gate. Three masked, gloved thieves were caught on surveillance cameras sliding down ropes from the store's skylights, outsmarting its sophisticated security system.

That night they got away, but they did leave evidence: DNA, found in a drop of sweat on a latex glove discarded next to a rope ladder used to reach the ground floor. Police ran the material through the German crime database. And they got a hit  two in fact. (See pictures of money being printed in Germany.)

The computer identified 27-year-old identical twins Hassan and Abbas O. (under German law they cannot be named in full). The unemployed and Lebanese-born brothers have lived in the northern German state of Lower Saxony since age 1 but still have not been granted permanent residency. They have criminal records for theft and fraud. (See pictures of the annual Twins Days festival.)

Police arrested the brothers on Feb. 11 in a gambling arcade and charged both with burglary, an offense that carries a potential 10-year prison sentence. But on March 18, before the case went to trial, they were released. The twins  who have made no comment on the charges  "are laughing at the rule of law in this country," opined Germany's mass-market daily Bild.

Here's the joke: the authorities had no choice, as the court ruling made clear: "From the evidence we have, we can deduce that at least one of the brothers took part in the crime, but it has not been possible to determine which one." Identical twins share 99.99% of their genetic information, and the tiny differences are impossible to isolate because of their nature; they tend to be spontaneous mutations limited to certain organs or tissues. "Identifying those [differences] would amount to dissecting the suspects," says Peter M. Schneider, a University of Cologne forensic expert. "Our hands are tied in a case like this," says criminal-law expert Hans-Ullrich Paeffgen of Bonn University. "The law doesn't allow us to detain someone indefinitely just because he is suspected of a crime. This may be different elsewhere. But I'd rather live in a country where someone guilty is not convicted for lack of conclusive evidence than in a place where innocent people are locked up."

This isn't the first time an identical twin has proved impossible to pin down. The genetic material can thwart paternity tests if both twins claim  or deny  fathering a child. In the U.S., a jury in a rape trial in Houston deadlocked in 2005 when the DNA recovered at the crime scene matched identical twins who had kidnapped their victim together. A year earlier in Boston, a suspected rapist blamed his identical twin when confronted with the matching DNA. Although he was already serving a sentence for a rape conviction, the jury could not agree on a verdict, and the judge declared a mistrial. Earlier this year, an identical twin suspected of drug-smuggling and sentenced to death in Malaysia was set free when the court could not prove beyond doubt whether he or his brother had committed the crime. (Read a TIME cover story on DNA.)

If fresh evidence emerges, a new arrest warrant can be issued against Hassan and Abbas O. anytime within the next 10 years, the statute of limitations for burglary cases. Police will continue to keep an eye on them, hoping to be led to the loot. But with the brothers' arrest warrants suspended, they are free to travel, and the authorities cannot tap their phone lines or keep tabs on their bank accounts.

"The mills of justice grind slowly, and sometimes not very finely," says Paeffgen dryly. The twins disagree. "We are proud of the German legal system and grateful," they told Berlin's daily Der Tagesspiegel through a family member after their release.

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