A 17-year-old girl who died Thursday at Kyoto University Hospital may have been killed by ethanol accidentally injected into her respirator, police said Tuesday, adding that they have launched a criminal investigation into the case.

Medical staff at the hospital, in Kyoto's Sakyo Ward, mistook a container of ethanol as distilled water and injected it into the teenager's respirator at least 10 times over a period of two days, hospital representatives said.

Hospital representatives have issued an apology to the victim and her family.