British nurse Lucy Letby, serving a life sentence for killing seven babies at the hospital where she worked, will be retried on charges of trying to kill another newborn, prosecutors said today, in a chilling serial killer case that has freeze the country.

After her conviction, Letby, who the judge said carried out a cruel and premeditated campaign of killings, with her actions bordering on sadism, was sentenced to life in prison, meaning that she will never be released from prison.

Letby, 33, Britain’s deadliest serial child killer in modern history, was convicted in August of murdering five newborn boys and two newborn girls at the Countess of Chester Hospital in northern England and attacking six more in 2015 and in 2016. However, jurors failed to agree on six counts of attempted murder involving five other infants.

At a court hearing, the prosecution announced it would pursue new trial on one of these countswith the trial date tentatively set for next year.

“These decisions about whether to retry the remaining charges of attempted murder are extremely complex and difficult,” said Jonathan Storer, lead prosecutor.

Police are also continuing to review 4,000 other admissions to neonatal units where Letby worked to see if there are possible other victims, while the government will investigate the case amid allegations from doctors that concerns about the nurse were not taken taken into account by the competent authorities of the hospitals.

“Before reaching our conclusions, we listened carefully to the views of the families affected, the police and the counsel for the prosecution,” the prosecutor said.

Earlier this month, lawyers for Letby, who maintains she is innocent, filed an application seeking leave to appeal against her convictions.