Who is the 'Angel of Death'? Japanese police fear hospital worker has killed 48 patients by poisoning their drips

Japanese police are hunting for an 'angel of death' serial killer who may have caused the deaths of 48 elderly patients at one hospital by poisoning their intravenous drips.

Suspicions were aroused after an autopsy showed that two elderly men were recently poisoned at Oguchi Hospital near Tokyo.

Victims Sozo Nishikawa and Nobuo Yamaki, both 88, died on September 18 and 20 respectively.

Autopsy results showed that they were killed by a chemical found in antiseptic. The chemical is the same as one in a disinfectant used at the Oguchi Hospital's nurse's station, Jiji Press news agency said. Intravenous drip bags were found pierced with the disinfectant inside.