By Selena Hill (staff@latinospost.com) | First Posted: Mar 28, 2013 04:44 PM EDT

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

While working at the Evangelical Hospital in the city of Curitiba, prosecutors say that Dr. Virginia Soares de Souza injected muscle relaxing drugs into patients before reducing their oxygen supply to intentionally caused them to die from asphyxia.  The 56-year-old widow also worked with a medical team to kill terminally ill patients.

She was arrested last month and charged with seven counts of aggravated first degree murder while her team of three doctors, three nurses and a physiotherapist have also been charged with murder.

Prosecutors for the state of Parana claim that De Souza's confessed her plot to kill patients in order to make money via phone conversations that were wiretapped. 

"I want to clear the intensive care unit. It's making me itch," she said in one recording released to Brazilian media. "Unfortunately, our mission is to be go-betweens on the springboard to the next life," she added in the same phone call.

However, De Souza's lawyer, Elias Mattar Assad, argues that investigators have misunderstood how an intensive care unit works and that the doctor is innocent.

Investigators are looking into 1,700 medical records of patients who died within the last seven years at the hospital while De Souza headed the ICU.

"We already have more than 20 cases established, and there are nearly 300 more that we are looking into," the chief investigator assigned by Brazil's Health Ministry, Dr. Mario Lobato, said on Globo TV's Fantastico program on Sunday.

Some of the patients were conscious moments before they died, he added.

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