Updated

A Brazilian doctor charged with killing seven patients to free up hospital beds may be responsible for up to 300 deaths, according to investigators.

Prosecutors claim that Dr. Virginia Soares de Souza, a 56-year-old who worked at the Evangelical Hospital in Curitiba, killed patients through asphyxia by giving them muscle relaxing drugs before reducing their oxygen supply, Reuters reports.

Investigators are analyzing 1,700 medical records of patients who died at the hospital for links to de Souza. Three hundred cases are being probed, a Brazil Health Ministry official told Globo TV.

De Souza has been charged with seven counts of murder, while three other doctors, three nurses and a physiotherapist where also hit with murder charges, Reuters reports.

De Souza was arrested last month but was released last week on bail pending the results of the investigation.

Her lawyer said prosecutors are misunderstanding how an intensive care unit operates.

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