LONDON (AP) — A British judge has sentenced Lucy Letby to spend the rest of her life in prison for murdering seven babies and attempting to kill six others while working as a neonatal nurse at a hospital in northern England.

Justice James Goss imposed the most severe sentence possible under British law on Letby Monday.

Following 22 days of deliberation, a jury at Manchester Crown Court convicted Letby, 33, of killing the babies during a yearlong spree that saw her prey on the vulnerabilities of sick newborns and their anxious parents.

The victims, including two triplet boys, were killed in the neonatal unit at the Countess of Chester Hospital in northwest England between June 2015 and June 2016.