Oslo police inspector Grete Lien Metlid told NRK: “We have thought a lot about it, my colleagues and people who have worked with this for many years.

“This is a special case, and it makes us ask questions about how it could happen.”

Neighbours say he was a bit reclusive, not wanting to talk to people much.

“Based on the picture we have, it is obviously a person who has chosen to have little contact with others,” Ms Lien Metlid told NRK.

The inflow of his pension money stopped in 2018 when the Norwegian Labour and Welfare Administration (NAV) couldn’t contact him anymore.

The money was obviously pooling nicely and because of all the automated payments set up, no authorities needed to chase him for outstanding bills.

“All his expenses were paid automatically from his bank account, everything was automatic,” said Prof Arne Krokan at the Norwegian University of Science and Technology.

“That’s something that would not have happened in the past. So if something strange happens, it’s possible nobody will notice.”