Neonatal nurse Letby was found guilty of murdering seven babies and attempting to murder six other infants, with the verdicts made public on Friday.

Since her conviction, many medical professionals have been questioned on what they think the motivation behind her horrendous crimes was.

Key pieces of evidence used within the prosecution's case were various handwritten notes, found within Letby's room when police searched her home in 2018.

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During the trial, the defence said the notes were the ramblings of an innocent woman, but consultant forensic psychiatrist, Dr Sohom Das, said these notes give a "glimpse into the psyche" of the most prolific child murderer of modern times in the UK.

The notes appeared to be some form of confession, with the words "I am a horrible evil person... I AM EVIL I DID THIS," among a page filled with text.

In another part, she wrote: "I don't deserve to live. I killed them on purpose because I'm not good enough to care for them."

"I can see the defence's angle, as we know Lucy Letby had a degree of anxiety and depression in the background and people particularly with depression have negative cognition, so they can feel guilty and shame even when it is not warranted," Dr Das told Sky News.

But he added: "To me, this was a little glimpse inside her psyche.

"I believe a tiny part of her felt some sort of remorse or shame even though it wasn't enough to stop her carrying out her heinous killings and it wasn't enough to make her tell the truth during the trial."

When asked what makes somebody "switch" from being a caregiver at the Countess of Chester Hospital to a serial killer, Dr Das suspected Letby "harboured dark murderous thoughts" for some while before actually harming any infant.

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'Getting away with it emboldened her'

"Another element to this whole case is the fact that she kept getting away with it," Dr Das said.

"Even when she was discovered, the complaints from the other doctors weren't taken seriously.

"I think this emboldened her. From her warped perspective, there was no reason to stop trying to escalate getting that thrill."

Dr Das admitted that without being able to examine Letby, or without a confession from her personally, it might never be possible to determine the motivation behind her actions.

The prosecution put forward the theory that it was to get the attention of a doctor she had a crush on, but Beatrice Yorker, a professor emerita of nursing and criminal justice and criminalistics at California State University in Los Angeles, said it does not appear as if the nurse was seeking attention.

Instead, she suggested it was an "act of covert violence or sadism" that motivated the nurse.

Another theory, put forward by criminal psychologist Dr David Holmes, is that Letby was "someone who was born with psychopathic tendencies".