Police in Vancouver say a man is facing identity-theft charges after British Columbians' personal information was allegedly accessed through the PharmaNet system.
An investigation was launched in February after police were notified that someone was fraudulently using information obtained through the data system.
"Information gathered confirmed that the suspect gained unauthorized access to the PharmaNet system and gathered patient's personal data," police said in a statement. "That information was then used for fraudulent purposes."
PharmaNet links all B.C. pharmacies to a central set of data systems and logs all prescriptions, maintains basic profiles that include names, addresses, dates of birth, personal-health numbers and medication histories.
Officers executed a search warrant in Richmond, B.C., last week and arrested one man.
Police said he is facing a number of identity-theft related charges.
The province said in a release on Monday that 20,500 people may have had their information viewed inappropriately, up dramatically from the 7,500 people originally believed to have been affected.
The government has said there were four incidents of "unusual" activity on the PharmaNet system and the breaches are alleged to be the result of cybercrime that targeted doctors' and medical offices and PharmaNet service vendors.
The Health Ministry has sent letters to people affected by the breaches and said they will be offered free credit monitoring, while a letter was sent to affected health-care practitioners, telling them how they can prevent unauthorized access.
In February, the ministry said it was first notified of the breaches last fall. Premier Christy Clark said then that she was "profoundly disturbed" by the incidents.
The province said on Monday that various ministries have done a "significant amount of work" since the breaches were discovered and "more robust" security measures will be implemented for PharmaNet and the system's vendors. It said the information and privacy commissioner has also been notified and is receiving regular updates.