An extortionist is now sending individual emails to a psychotherapy centre's patients asking them to transfer hundreds of euros in Bitcoin to stop their patient records being published online.
As well as their personal data, the extortionist told them that records of their discussions with therapists would be published.
It is not known whether the extortionist is the same individual or group that hacked the data in the first place.
Individual emails were sent on Saturday evening, with Yle receiving messages from 8pm onwards. All the victims described receiving the same message.
The extortionist wrote that recipients must pay 200 euros within 24 hours, or if they don't meet that deadline, 500 euros within 48 hours.
Messages demanded that the payments be made in Bitcoin.
The extortionist threatened to publish personal data and records psychotherapy sessions if victims did not pay up.
Police advised victims not to comply with the demands, to report the message and their contents to police, and to keep the message and any other evidence safe.
The National Bureau of Investigation (NBI) said it is impossible to say whether the extortionist is the original hacker or not.