Some 300 deaths at a Brazilian hospital are being studied for possible links to a medical team charged with murder.
Dr Virginia Soares de Souza and seven assistants at an intensive care unit in the city of Curitiba are already charged with killing seven patients.
But an investigator told Brazil's Globo news channel that another 20 deaths were suspicious and a further 300 were being looked into.
Dr de Souza denies the murder charges along with her former staff.
She was arrested in February and released on bail last week.
But prosecutors have sought to have her returned to custody in light of her alleged leadership role in orchestrating the deaths.
Dr de Souza - said to be a 56-year-old widow - worked at the Evangelical Hospital in Curitiba in the south of Brazil.
Prosecutors say she gave muscle-relaxing drugs to patients before reducing their oxygen supply, causing them to asphyxiate.
She has been charged with seven counts of aggravated first-degree murder.
Three doctors, three nurses and a physiotherapist who are suspected of carrying out her orders have been charged with murder.
But the medical records of 1,700 patients who died at the hospital in the last seven years are now being studied and more than 20 were now deemed suspicious, Dr Mario Lobato - the chief investigator assigned by Brazil's health ministry - told Globo.
"There are nearly 300 more that we are looking into," Dr Lobato said.
According to Reuters news agency, state prosecutors have released wiretaps which apparently show that her motive was to free up beds.
"I want to clear the intensive care unit. It's making me itch," she said in one recording.
"Unfortunately, our mission is to be go-betweens on the springboard to the next life," she added.
Physiotherapists, dieticians, nurses and nursing technicians are said to have reported their fears that she was hastening the deaths of critically ill patients.
But Dr de Souza claims those accusing her lack the expertise to make a correct judgement.
"We will soon prove that everything that took place in that ICU [intensive care unit] is justified by the medical literature," her lawyer Elias Mattar Assad told Globo.