Nurse Lucy Letby was "completely out of control" when she attacked three babies on her return from a holiday in Ibiza, a court has been told.
Prosecutor Nick Johnson KC said Letby, 33, had "got away with so much" at that point it gave her the "misplaced confidence that she could pretty much do whatever she wanted" at the Countess of Chester Hospital's neonatal unit. Letby is alleged to have murdered seven babies and attempted to murder 10 others between June 2015 and June 2016.
On three successive days in June 2016 she is said to have murdered two triplet boys, Child O and Child P, and attempted to murder another baby boy, Child Q.
READ MORE: Lucy Letby cries in dock as she's quizzed over 'I am evil, I did this' note
The Crown say Letby, from Hereford, murdered Child O by injecting him with air intravenously and via a nasogastric tube, as well as using "significant force" to inflict a liver injury.
Continuing his closing speech at Manchester Crown Court, prosecutor Nick Johnson KC told the jury of eight women and four men that Child O's case had similarities to Letby's alleged murder of Child E, a twin boy, in August 2015 who bled profusely before his death.
He said: "We say simply, ladies and gentlemen, that the murder of (Child O) was cruel and it was violent. All of the offences on this indictment were appalling examples of attempts and completed murders.
"Some of the earlier offences were less overtly violent but no less devastating. We say Lucy Letby used violence and air on (Child E). Unfortunately, there was no evidence from a post-mortem on what injuries caused him to bleed.
"But no doubt she had got away with so much by the time she returned from Ibiza it gave Lucy Letby the misplaced confidence that she could pretty much do whatever she wanted. Her objective, as always, was to kill.
"In (Child O's) case she combined all three methods she had used to such devastating effect on all the other children in the case. In order to try to cover up what she did, she falsified the notes.
"We say, frankly, by this stage she was completely out of control and was determined to mete out the same treatment to (Child P) the very next day."
Mr Johnson said Letby returned from her break in Ibiza with two friends shortly after the birth of the naturally conceived triplets on June 21 2016.
He said that text messages she sent revealed she was "excited at the prospect of seeing them" on her return to the unit on June 23. Mr Johnson said: "Unfortunately for them her objective was to kill at least two of them."
On the afternoon of June 22, Letby texted a friend: "Probably be back in with a bang lol."
The prosecutor said: "Within 72 hours of that text message, two of the triplet brothers were dead and she tried, we say, to kill (Child Q)."
Letby denies all the allegations. The trial continues.
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