Lucy Letby likely murdered or assaulted more babies before she killed her first known victim, a senior paediatrician told a public inquiry today.
Dr Stephen Brearey said he now believes collapses and deaths of other children before June 2015 were suspicious.
Although he insisted that neither he or his consultant colleagues recognised a member of staff could be deliberately causing harm prior to that date.
Neither me or my colleagues had concerns at the time, we just thought we were going through a busy patch or a particularly difficult patch, he said.
Peter Skelton KC, who is representing families of children murdered or harmed, said: You made a statement that on reflection you thought it is likely Lucy Letby didnt start becoming a killer in June 2015, Baby A was murdered on June 8.
Is it your view that she had murdered or assaulted children in your hospital prior to that date?
Dr Brearey, the lead consultant for the neo-natal unit at the Countess of Chester Hospital, replied: I think thats likely, yes.
Mr Skelton added: On reflection now, do you look back and see a number of unexpected collapses or deaths, which with information now available to you appear suspicious?
Lucy Letby likely murdered or assaulted more babies before she killed her first known victim, a senior paediatrician told a public inquiry today. Pictured: Lucy Letby
Dr Stephen Brearey (pictured) said he now believes collapses and deaths of other children before June 2015 were suspicious
Letby was found guilty of murdering seven newborn babies and attempting to kill six others between 2015 and 2016
Yes, the medic added.
Letby, 34, was convicted of murdering seven infants and trying to kill seven more on the unit between June 2015 and June 2016.
However, Cheshire polices investigation is ongoing and detectives are examining 4,000 babies she cared for during the footprint of her career, dating back to 2012, including two placements she undertook as a student at Liverpool Womens Hospital, in 2012 and 2015.
The inquiry has already heard from a registrar, Dr Rachel Lambie, who said around a fortnight before Letby murdered Baby A – a premature twin boy who was her first victim - another very, very unusual event had occurred on the ward.
Although she didnt go into details, Dr Lambie confirmed shes given a statement to Cheshire police about the incident.
Dr Brearey said that, prior to June 2015, staff on the unit didnt realise the thermostat had been turned up, with more babies suffering problems or events they didnt understand, because they initially tried to normalise what was happening by finding medical reasons for infants falling unexpectedly ill.
We work in the NHS, its not perfect, and there are lots of rational ways to explain away (which) looking back on it, it doesnt make sense, he added.
Blaming the transport service, blaming another Trust for sending babies back when werent completely stable, rather than taking a step back and thinking whats happening here?
This is the moment former neo-natal nurse Lucy Letby was arrested at her home in 2018
Letby was convicted of murdering seven babies and attempting to murder six others while working at the Countess of Chester Hospital
He added: In retrospect, although I thought our reporting culture on the unit was good and that staff were very aware to report things that they thought went wrong, I think some of the incidents occurring in the indictment period and probably before were babies that deteriorated that could have triggered an incident.
On reflection I think its likely that Letby didnt start becoming a killer in June 2015, or didnt start harming babies in June 2015, I think its likely that her actions prior to then over a period of time changed what we perceived to be abnormal.
Dr Brearey said after Letby was redeployed into an administrative role, following the deaths of her two final victims, two triplet brothers, a year later in June 2016, there was so much secrecy and intimidation from senior hospital managers directed towards the consultants that it felt like they were working in North Korea or the old East Germany.
At some point in 2017, Dr Brearey also described having an uncomfortable conversation with the parents of a child not involved in Letbys trial, who he feared had been murdered, but who he could not be open with.
He said: I remember feeling quite awkward about the concerns they had. I could easily answer in terms of specifics, they could tell something wasnt quite right, their senses were up.
It didnt sit with me at all well and I felt very uncomfortable doing it, but I didnt feel in a position to let them know I was worried about a nurse murdering their baby, as well as others.
The inquiry, sitting at Liverpool Town Hall, is expected to sit until early 2025, with findings published by late autumn of that year.