This article is more than 1 year old

This article is more than 1 year old

The wife of a Norwegian multimillionaire missing for 10 weeks has probably been kidnapped and a ransom has been demanded for her release, police have said.

Married to a real estate and energy magnate, Anne-Elisabeth Falkevik Hagen, 68, disappeared on 31 October, police said.

“A ransom demand and serious threats have been issued,” Insp Tommy Brøske told reporters.

“Our main theory is that the victim was kidnapped by unidentified perpetrators at her home” in Lørenskog, about 12 miles (20km) from Oslo, he said, adding that police had from the beginning examined several possible theories about her disappearance.

Facebook Twitter Pinterest Anne-Elisabeth Falkevik Hagen. Her husband, Tom Hagen, is Norway’s 172nd richest man. Photograph: Police handout/AP

Police have received no proof that the woman is alive “but we haven’t received any indication that she isn’t alive either”, Brøske said.

The cautious nature of the remarks could be an indication that police have not received proof that Hagen was indeed being held by the people demanding the ransom. Police said they had no suspects at this stage.

According to the daily newspaper Verdens Gang, the ransom demand was for €9m (£8m) in the cryptocurrency Monero.

Investigators refused to confirm the amount but said they advised the family not to pay the purported kidnappers.

Such events are extremely rare in the Scandinavian country, which enjoys a generally low crime rate.

Facebook Twitter Pinterest Police inspector Tommy Brøske at a press conference in Lillestrom on Wednesday. Photograph: Ole Berg-Rusten/EPA

Police have been investigating the case discreetly for several weeks but decided to make it public in the hope someone would come forward with information, Brøske said.

Brøske said investigators had had “very limited” contacts with the purported kidnappers online, but refused to disclose the date of the most recent contact.

The missing woman’s husband, Tom Hagen, also 68, is Norway’s 172nd richest man, according to the magazine Kapital, with an estimated fortune of 1.7bn kroner (£156m).

The real estate investor owns 70% of the electricity company Elkraft, which he co-founded in 1992, Norwegian media reported.