Prosecutors in Uruguay filed murder charges on Sunday against two nurses for at least 16 mercy killings, and jailed the suspects, the judge in charge of the case said.
The male nurses, 39 and 46, were charged with homicides of patients both at a private Neurological Intensive Care Center and a public hospital's intermediate-level care unit.
A girlfriend of one of the men was charged with covering up information related to the case.
Judge Rolando Vomero, who is in charge of the investigation, has not said exactly how many deaths are being probed in total. But he said that so far, one of the suspects has admitted to 11 killings and the other to five.
Defense attorney Ines Mazziotti said the killings were for 'mercy'.
"After 20 years (working) in intensive care, or constant stress on the edge of life and death, he could not take it anymore," she said of one of the suspects, who were not immediately identified.
The nurses worked separately and barely knew one another, local daily El Pais reported. More than 50 deaths could be involved overall, the paper said.
The Health Ministry also has voiced 'deep concern' and says it is working to help move the investigation along.