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COPENHAGEN, Denmark — Norway's police said Wednesday the missing wife of one of Norway's richest men has been abducted, and that her suspected kidnappers have demanded a ransom.

Chief investigator Tommy Broeske said 68-year-old Anne-Elisabeth Falkevik Hagen has been missing since Oct. 31. Her husband Tom Hagen — a media-shy real estate investor and owner of power facilities — is number 172 on a list of the country's 400 most wealthy people published by Norway's financial magazine Kapital. His fortune in 2018 amounted to nearly 1.7 billion kroner ($2 billion), according to Norwegian news agency NTB.

Police said a note found in the couple's house, east of Oslo where they lived "a rather anonymous lifestyle," according to Norwegian broadcaster NRK, described what would happen to her if the demanded ransom wasn't paid in the cryptocurrency Monero.

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Police did not give a figure for the ransom amount, but Norway's VG newspaper reported it was 9 million euros ($10.3 million).

Anne-Elisabeth Falkevik, the wife of Norwegian multi-millionaire Tom Hagen, has been missing since Oct. 31, 2018. Norwegian Police / AFP - Getty Images

The newspaper reported that the note said Falkevik Hagen would be killed if police were involved. Broeske declined to comment other than saying "the threats (in the note) were of a very serious character."

"The reason for us to go public with this case now is that despite a broad and extensive investigation, we need more information," Broeske told a news conference.

He said police had no suspects so far. Police have been "on the case for several weeks. That is all I'd say," he added. Police had no indication whether Falkevik Hagen was dead or alive.

Broeske said "those behind have chosen to communicate digitally and we have had no other type of contact." Police had urged the family not to pay any ransom.

Svein Holden, Hagen's lawyer, told reporters the abduction was "a cruel and an inhuman act." ''It is demanding and exhausting to be in such a situation over a long period of time," he said.

Police believe she disappeared from the couple's home, some 31 miles from the Swedish border. Broeske said they were working with Europol and Interpol on the case.

Justice Minister Tor Mikkel Wara told NTB that he was informed about her disappearance "right after it happened."