Police investigate mystery penguin death at Dortmund zoo

Humboldt penguins are a South American species that breeds in Chile and Peru

Police in the German city of Dortmund are investigating the death of one penguin and the disappearance of two others from the local zoo.

On Monday morning zookeepers found one Humboldt penguin lying dead in its cage and two others missing, police spokesman Marco Mueller said.

It is the latest in a string of mysterious incidents at Dortmund Zoo.

Last month a sea lion was found dead with a smashed skull. In August three pygmy marmosets were stolen.

Mr Mueller says it is not clear whether the incidents are linked.

Police are trying to determine whether the penguins were targeted by thieves.

A post-mortem examination is being carried out on the dead bird, the zoo said.

Security at the zoo has been stepped up.