A mother from Greater Manchester waited 10 hours to go to hospital with her distressed baby son who died from a severe head injury inflicted by her housemate, a jury has heard.
Seven-week-old Thomas Gacek is said to have been assaulted while his Polish mother, Katarzyna, was out shopping.
When she returned to their home in Oldham she noticed a cut and bruising around her son's lip and was told by fellow Pole, Dawid Mokrzanowski, he had fallen asleep and that Thomas must have banged his mouth on the frame of his rocking cradle.
Preston Crown Court heard the youngster was admitted to Royal Oldham Hospital on the late evening of January 25 with multiple bruises all over his body, severe retinal bleeding in both eyes and was noted to be pale, unresponsive and having a seizure.
He was transferred to Manchester Children's Hospital but was pronounced dead two days later.
Prosecutor Raymond Wigglesworth QC said Thomas's body was examined by a number of medical experts including a consultant paediatrician who concluded the number of bruises - 25 different sites - were "suggestive of inflicted injuries and are not consistent with accidental injuries to a non-mobile baby".
He added: "In particular she noted that the injuries to both ears were unusual and would suggest either an impact with a hard surface or that he had been slapped across the face."
The post-mortem examination also revealed that Thomas had four fractured ribs said to have been caused in the days before he suffered the fatal head injury.
Mr Wigglesworth said the expert view was that the most probable cause was non-accidental and the amount of force required would be "considerable, even on a baby of this age".
There was also evidence of a minor bleed to the brain in the same period as the broken ribs, the jury was told.
The prosecutor said Gacek, 24, came to the UK in 2010 but had no contact with Thomas's father who was unaware the child was his.
Mokrzanowski, 26, lived with them in Hillside Avenue and often acted as carer for her son, as did Gacek's boyfriend, Darren Butterfield, 35, a frequent visitor to the address.
Mr Wigglesworth said: "The prosecution say that up to and including the health visitor's examination of Thomas on January 17 he was a healthy, growing baby with no medical problems.
"We know at some stage between January 22 and January 25 someone within that household unlawfully caused injury to Thomas either by striking him or squeezing him, causing four fractures to the ribs on the left side of his body."
On January 25, Gacek left the baby in the house with Mokrzanowski at 9am and did not return until 1pm, the jury heard.
She found Thomas in a rocker in the downstairs bedroom of her compatriot who was asleep and when she confronted him about the injuries to his face he told her it must have been an accident.
Butterfield later arrived at the house just after 2pm, said Mr Wigglesworth.
All three defendants initially told medics and police that Gacek was alone in the house all day and she accidentally tripped on the stairs, dropped her son and then fell on him.
Each later changed their accounts but the prosecutor said the jury was entitled to ask whey they had told "a pack of lies".
Mr Wigglesworth said: "Why did the three defendants agree to lie about what happened to Thomas? Was it because they feared the Social Services coming in asking questions or was there some other motive for shielding the truth from the hospital staff and police?"
It emerged that Gacek and Mokrzanowski made a number of Google searches in the hours before Thomas was taken to hospital in which they inquired about head injuries to babies.
Butterfield told police that during the internet searches his co-defendants were sat on the sofa with his girlfriend reading out the symptoms, including "the baby staring in one place".
Mr Wigglesworth told the jury: "The prosecution case against these three defendants is that they were each involved in a series of events which led to the unlawful killing of this baby."
All three defendants deny causing or allowing the death of a child.
Mokrzanowski has also pleaded not guilty to manslaughter.