It is like a high-tech game of Cluedo. A dozen A-level chemistry students meet in a laboratory, their mission to solve a complex murder mystery. The victim is Kenny, the character who gets killed every week in the cult television series South Park.

The three main suspects are his cartoon friends Kyle, Stan and Kartman. But there are far more scientific techniques at work here than we used discovering it was Colonel Mustard in the library with the candlestick.

Under the fingernails of poor old Kenny police have found scales of skin that they believe came from his attacker during a struggle. From this, forensic scientists have been able to extract a sample of the killer’s DNA and we are in the lab to match this against DNA taken from the three suspects. This is what Cluedo could have been like if they had known about DNA fingerprinting in Agatha Christie’s day.

The exercise is entertaining and fun because there is no one in the lab who has not seen the cartoon series. But it is also highly educative and practical, as students dye three different DNA samples, run them through a gel using electrophoresis and match them against the DNA pattern of the killer.

The class is part of the Excellence in Cities Millennium Summer School at London’s Institute of Education. Heading the murder investigation is Dr Dominic Delaney, a research neuroscientist and specialist in scientific communication, who runs a range of such practical workshops for 14 to 19-year-olds. “DNA fingerprinting is a basic research technique,” he says. “But I wanted to find a way of communicating quite complex concepts hich was at the same time engaging and relevant.”

His approach works. Susan O’Loughlin, a Year 12 chemistry and biology A-level student from Maria Fidelis school, Camden, is most impressed. “The story makes it much more interesting. The scientific techniques are fascinating but this adds an element of fun. It’s totally different from the way science is taught in school, which is mostly copying out of textbooks,” she says. Her money is on Kartman.

While they wait for their gels to run and reveal the unique DNA structure that will solve the crime, Dr Delaney leads a discussion on the practical applications of DNA fingerprinting and its moral and ethical implications. Using slides of relevant newspaper cuttings and other pictures, he asks a series of pertinent questions. Are there civil liberties issues involved? What about cloning? Indeed, should we lock up Kenny’s killer on the evidence of DNA fingerprinting alone?

Mustafa Anjari, a Year 12 student from Hampstead school, suspects Kyle of the evil deed.

“It’s very different from school science,” he says. “You don’t usually get the chance to discuss the issues behind the techniques because it’s outside the curriculum. You can do the exercise perfectly well but still not necessarily understand why you are doing it.”

In case you were wondering whodunnit, it was Stan. Watching South Park will never be quite the same again.

For details about Dominic Delaney’s workshops, tel: 020 8363 2652 or e-mail: d.delaney@btinternet.comEnquiries about the science summer school should be addressed to Dr Jenny Frost, Department of Science and Technology, Institute of Education, 20 Bedford Way, London WC1H 0AL