A Russian academic investigating the fate of ethnic Germans deported by Stalin during World War II has had his research seized by security services.

History professor Mikhail Suprun was briefly arrested in the far north of Russia last month, but the incident has only now come to light.

Prof Suprun told the BBC he has been ordered not to comment on the case.

Prof Suprun had managed to track down the files of 5,000 deportees and had interviewed hundreds of their descendents.

But now the documents he had collected over 10 years, his computer and all his hard drives have been seized by the FSB - the powerful successor to the KGB.

Although he has been ordered not to comment on the case, a few days ago he described the seizure as absurd.