Human bones and a skull have been unearthed by workmen in a zoo in Plock, around 100 kilometres from Warsaw in central Poland.

Plock’s mayor Miroslaw Milewski told the PAP news agency that bones, including a skull with a hole in it, were found when workers were laying water supply pipes to one of the zoo’s facilities.

“It’s difficult to say how many skeletons were buried there. There are plenty of bones and more may be found,” added the mayor.

The discovery site has been fenced off but visitors are still being welcomed to the zoo.

The remains possibly date back to WW II but as yet investigators have failed to be able to date them.

The Prosecutor’s Office in Plock has opened an investigation into the case.

“No personal belongings or documents were found near the skeletons so it will be difficult to establish their identity,” said Milewski.

The mayor revealed that several years ago a man contacted the zoo claiming that during WW II Nazis shot people there. “Back then we searched for remains but did not find anything,” said the mayor.

The zoo in Plock was founded in 1951. There are about 3,700 animals there, representing 320 species. (pg/mg)