A neonatal ward manager at Lucy Letby's hospital outlined 15 reasons why the nurse could not be to blame for the deaths and collapse of babies, it has emerged.
Documents released for the Thirlwall Inquiry, which is examining how incidents at the Countess of Chester could have been prevented, show that Eirian Powell, Letby's boss, was unconvinced by allegations against the nurse.
She distributed a document entitled "Neonatal Unit review 2015-2016" in May 2016, which gave 15 reasons why it was unlikely there was a baby killer on the ward.
"There is no evidence whatsoever against LL (Lucy Letby) other than coincidence," she wrote.
"LL works full time and has the qualification in speciality (QIS). She is therefore more likely to be looking after the sickest infant on the unit, LL is also available herself to work overtime when the acuity of the unit is over capacity."
The neonatal ward manager went on to point out that the spike in deaths could be accounted for by failings on the unit and elsewhere as well as health problems with the babies.
Ms Powell argued that two of the babies were diagnosed with congenital pneumonia, two had necrotising enterocolitis - a dangerous complication for preterm infants - one mother had a maternal syndrome and one baby had overwhelming sepsis.
"Some of the issues were related to midwifery problems," she added. "The Cheshire and Mersey transport service have been involved in a few of these mortalities and they may have survived if the service was running adequately."
She concluded: "Of all the post results there was no evidence of foul play."
Ms Powell also pointed out that two doctors, Dr John Gibbs and Dr Dave Harkness, had been present at several of the incidents.
Letby was convicted of murdering seven infants and attempting to murder seven more at the Countess of Chester Hospital between 2015 and 2016.
Since the verdicts, many scientists, statisticians, doctors and nurses have come forward to question the evidence given to the jury, who were not told about several reviews undertaken by the hospital to find out what was causing the spike in deaths. They largely pointed to overcrowding, sub-optimal care, understaffing and transfer issues.
A document released this week by the Thirwall Inquiry from Stephen Cross, the director of corporate and legal affairs at the hospital, also showed that the Countess of Chester contacted police reluctantly in 2017.
"In our view, there is no evidence to justify a criminal investigation," he wrote. "However, in the spirit of openness and transparency, the matter is being reported to the police, having regard to the fact that a number of consultant paediatricians are not satisfied with the very thorough investigations and reviews undertaken.
"Twelve of the deaths have been subject to post-mortem, but there have been no suspicious findings.
"A secondary review of four deaths, by pathologists at Alder Hey Children's Hospital, did not raise any concerns regarding unnatural causes of deaths."
This week, Dr Stephen Brearey, a paediatric consultant at the hospital, gave evidence at the Thirlwall Inquiry and was asked about Ms Powell's list of reasons. Dr Brearey was one of the first doctors to raise concerns about Letby and called for her to be removed from the unit.
He said that he felt Ms Powell had strayed into areas of expertise that were beyond her training.
"Saying there is no evidence whatsoever other than coincidence overlooks the timing of the deaths and the sudden, unexpected nature of the deaths," he told the hearing. "The increase in numbers above anything we'd expected.
"The babies had congenital abnormalities but the point and the level of concern was that it wasn't clear from the post-mortem results that those congenital abnormalities had led to the sudden collapses.
"Dr Harkness and Dr Gibbs, appear to be involved in many mortalities. Well, they were involved more than some of the other doctors but it was still less than half of the episodes that Letby had been involved with."
The prosecution say that Letby was convicted on a multitude of evidence from specialists and that the defence could have called rebuttal witnesses but chose not to.
The Thirlwall Inquiry continues next week when it will hear from management at the Countess of Chester Hospital.