Singapore's health ministry has accused an American of stealing and leaking the records of 14,200 people infected with HIV, the virus that causes AIDS, before January 2013.
The ministry said Tuesday that Mikhy K Farrera Brochez recently put the records online.
It said they included HIV test results, names, identification numbers, phone numbers, addresses and other health information.
The ministry said it has disabled access to the information.
It said Brochez worked in Singapore for a period before he was jailed for several drug and fraud-related offenses and deported last year.
The ministry said his partner, who headed the ministry's National Public Health Unit from March 2012 to May 2013, had access to the confidential information.
Police are investigating and authorities are seeking help from foreign counterparts.