Patients watch piano performance in Taiwan University Hospital in Taipei, southeast China's Taiwan, Aug. 30, 2011. The Taiwan University Hospital transplanted the organs of an HIV-infected donor on Aug. 24, putting five organ transplant recipients at high risk for contracting AIDS. The Taipei prosecutors office Tuesday began probing a case in which local hospitals unknowingly used organs from an HIV-positive donor in five transplant surgeries. (Xinhua/Li Hanfang)