A German man has been jailed for life after putting poison in his colleagues' sandwiches, leaving one in a coma and two others with serious kidney damage.

The man, 57, named only as Klaus O, was arrested last year after he was caught on video putting a suspicious powder on a colleague's sandwich.

When police searched his home they found a makeshift laboratory and a substance that Judge Georg Zimmermann described as "more dangerous than all combat agents used in World War II".

The man, who worked at a metal fittings company in Schloss Holte-Stukenbrock, north west Germany, refused to speak during his trial and his motives remain unclear.

Prosecutors believe he wanted to see his colleagues' physical decline.


Two of them, a 27-year-old and the other aged 67, suffered chronic kidney damage from poisoning with lead and cadmium and both men now face an increased risk of cancer.

A 23-year-old trainee fell into a coma after ingesting mercury and has permanent brain damage.

The judge said the court considered the crimes to be as serious as homicide and ordered that Klaus O be detained in prison after completing the life sentence - which is usually 15 years in Germany - because he remains a danger to the public.

The man's lawyers plan to appeal.