Police have arrested a man accused of distributing poisoned marzipan hearts at a school in Germany's north and blackmailing a supermarket chain for a sum of 3 million euros ($A4.4 million).
The man, who has been dubbed the "marzipan blackmailer" by German media, was arrested overnight in the northern city of Kiel, a police spokesman said on Monday.
He is accused of distributing the tainted sweets at a Kiel school last week and threatening to do so at other schools if the supermarket chain Coop failed to pay him the money.
Experts who examined the marzipan hearts said they contained a substance that was not life-threatening but could bring about severe health problems.
