Senior paediatrician Dr Ravi Jayaram had to resuscitate a baby girl after walking into a nursery room at the Countess of Chester Hospital where her breathing tube had been dislodged.
Former neonatal nurse Letby was later convicted of the attempted murder of Child K in February 2016.
The prosecution at Letby's trial said she was caught "virtually red-handed" by him, although he did not alert the hospital.
Giving evidence at the Thirlwall Inquiry, which is looking into the events surrounding the crimes, Dr Jayaram said he had been sitting outside the nursery reading medical notes when he realised Letby was alone with Child K.
This story is from the {{IssueName}} edition of {{MagazineName}}.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber ? Sign In
This story is from the {{IssueName}} edition of {{MagazineName}}.
Start your 7-day Magzter GOLD free trial to access thousands of curated premium stories, and 9,000+ magazines and newspapers.
Already a subscriber? Sign In
BARRY: WE'RE NOT AN ISLAND
Hearn: Fans must move with the times and accept foreign owners
STING WHEN I'M WINNING
Rory goes for his sixth European Order of Merit crown... but admits US Open meltdown still hurts
On stage, on screen, on canal boat... just the best
Over a 60-year career on stage and screen, Timothy West has taken on many titles - King, Prime Minister, Professor, Private. He was a captain of industry, a father figure and a love interest.
'I should have been braver over Letby'
THE TV doctor who helped expose Lucy Letby has told an inquiry he should have had more courage in voicing his concerns.
CAR THAT PROVES WHY Cop MATTERS
Spain set for more floods | PM calls for climate action
My Chitty Chitty banger
Model-maker, 92, turns old scooter into magical car
'Woman trafficked by AI Fayed saw enough photos of victims to fill shoebox'
Accuser calls on brother to give evidence of the alleged crimes of store tycoon
MEDICS ALLOWED AN OPT OUT ON ASSISTED DYING
Streeting: Moral objections a 'red line'
ELONATICS TAKING OVER THE USYLUM
Ridicule as Musk joins Trump's team | He surrounds himself with loyalists
PHARMACISTS VOTE FOR WORK TO RULE
Cuts and closures force move