Brazilian doctor Virginia Soares de Souza could be more prolific than Harold Shipman if it is proved she killed up to 300 patients to free up beds

A Brazilian doctor charged with killing seven patients to free up hospital beds for those with private health insurance may have been responsible for up to 300 deaths, the country’s Health Ministry has said.

Officials investigating Virginia Soares de Souza, 56, are reviewing more than 1,800 medical records at the hospital where she was the head of intensive care since 2006. If the number of deaths suspected of being linked to Ms de Souza is proven, she would have been a more prolific serial killer than British doctor Harold Shipman, who was found to have killed at least 215 people.

Ms de Souza, a widow who worked at the Evangelical Hospital in the city of Curitiba, the capital of the southern state of Paraná, is accused of masterminding a “gang of death” involving several members of her medical team. Three anaesthetists - Edison Anselmo Silva Junior, Maria Israela Cortez Bocato and Anderson de Freitas - were also arrested last month while another 13 doctors and 34 nurses have been transferred out of the department.

She is suspected of repeatedly giving patients the muscle relaxing drug Pavulon and turning off their oxygen machines. One nurse interviewed on Brazilian television, who worked in the hospital from 2004 to 2006, said she saw de Souza turn off a life-support machine, killing a patient.

Marcus Michelotto, inspector general of the Civil Police of Paraná, said: “We have been investigating this for about a year. There was sufficient evidence to require the arrest as a medical precaution.”

According to reports in Brazilian press the case came to light after a complaint was made to the health watchdog last year. Since then, at least 50 other complaints have been filed. State prosecutors claim they have telephone recordings that reveal Ms de Souza was driven by a desire to clear beds in the hospital for other patients, whose health care was funded privately. She allegedly said in a phone conversation: “I want to clear the intensive care unit. It’s making me itch. Unfortunately, our mission is to be go-betweens on the springboard to the next life.”

Police added it was unlikely she was working alone given the number of suspected suspicious deaths.

De Souza denies the charges and defended her record at the hospital where she has worked since 1988. In an interview with Fantastico earlier this month, which was approved by magistrates, she said: “I was never careless, I’ve never been reckless, never had an ethical breach or a complaint registered against me, and I practised medicine consciously and correctly.” She said any errors that happened were not intentional.

Last month, her lawyer, Elias Mattar Assad, issued a statement saying the police lacked evidence. “The police are not able to prove a criminal act. They show a body and say that his death happened because of a reason other than that on the death certificate? I challenge them to prove it”

But prosecutors said Ms de Souza would have felt “all powerful” and believed she “had the power to decree the moment when a victim would die.”

It is alleged that in some cases, she gave orders over the telephone to other doctors, according to court documents. Last week, a Curitiba judge ordered the release of Ms de Souza and her medical team on bail. On Monday, police filed a fresh request to arrest her on the grounds that she was the ringleader of the gang and could coerce witnesses. She appeared in court today as part of the requirement to report monthly while the case is ongoing.