Nurse Lucy Letby lied when she said she could not remember a baby girl who she allegedly murdered, a jury has heard.
Prosecutor Nick Johnson QC told Manchester Court that Letby, 33, did not want to admit the truth because it was "bad for her".
Continuing his closing speech on Wednesday, Mr Johnson reminded the jury of eight women and four men about a text message the defendant sent a colleague the morning after the death of Child D.
The message read: "So upsetting for everyone. Parents absolutely distraught, dad screaming."
Letby, from Hereford, is accused of murdering seven babies and attempting to murder 10 others at the Countess of Chester Hospital's neonatal unit.
She is said to have murdered Child D on a night shift which began on 21 June 2015, which was Father's Day.
Letby allegedly injected air intravenously into Child D's circulation while the infant's designated nurse was on a break.
Mr Johnson said there were no problems until Letby's colleague left nursery one at 1am.
He said: "Just as in the cases of (Child C), (Child G), (Child I), (Child J), (Child K) and (Child N) - all of them collapsed when their designated nurse left the room or went on a break.
"When she gave evidence Lucy Letby claimed to you that she didn't really remember (Child D).
"She said that to you because that's what she told the police in interview, and she said that in interview because she thought the absence of her name from the paperwork for (Child D) gave her the opportunity for plausible deniability.
"What she didn't realise and what she has now not taken account of is through the hard work of the police they can put her in the room."
The prosecution claim Letby frequently falsified medical records to "cover her tracks".
He suggested the defendant had twice mis-recorded that she was attending to other children in nursery one at the same time as two of Child D's three collapses on the shift.
The prosecutor also pointed out an unsigned blood gas reading of Child D at 1:14am which he said Letby admitted was in her handwriting.
Mr Johnson said: "She said the lack of signature was an oversight and an 'error that happens from time to time'.
"While people do forget things in a busy neonatal unit... we all make mistakes but it's the timing of the 'errors', isn't it. It's the pattern of the errors.
"It's the power of circumstantial evidence."
Another chart reading showed an intravenous infusion of liquid for Child D recorded at 1.25am and co-signed by Letby and designated nurse Caroline Oakley, he said.
Mr Johnson said: "Caroline Oakley, who was not actually there at the time, couldn't explain it.
"This is clear evidence, isn't it, that Lucy Letby in the absence of Caroline Oakley gave an intravenous injection of air to (Child D) five minutes before she collapsed."
Child D collapsed again at 3am and then finally at 3.45am, the court heard.
Mr Johnson reminded jurors about an answer she gave to her own counsel last month.
He said: "She was being asked about the effects of the deaths on the unit and the staff and she said, without any trace of irony, 'you don't forget things like that, they stay with you'.
"It is the same person whose case is that she doesn't remember this child who collapsed three times and died."
Letby searched on Facebook for Child D's mother three days after the infant's death and then for Child D's father more than three months later.
She said she could not explain why she had made the online searches, he said.
Mr Johnson said: "If she has a very good memory for names, then her claim to you was a lie.
"You might ask yourself why won't she tell you the truth? Because the truth is bad for her. It's bad."
Letby denies committing the alleged offences between June 2015 and June 2016.