A young mother sobbed uncontrollably as her husband admitted killing their baby daughter.

Updated 6 December

A Perth man who admitted to killing his baby, ignored repeated pleas from his wife to take the child to hospital after she had fallen off a change table, the Supreme Court has heard, reports ABC news.

Paul James Cosgrove, 24, was looking after his seven-month-old daughter Lily in September last year when he left her alone on the table to dispose of a used nappy.

The court was told when he went back into the room he found the child on her back on the floor, but despite her making funny noises he did not seek any medical attention.

Cosgrove was looking after the child because his wife Emma had returned to full-time work.

She telephoned him and after he told her about the baby’s condition, she pleaded with him to take Lily to hospital but he refused and instead returned home.

Prosecutor Amanda Burrows said when Ms Cosgrove arrived at the house, she found her husband “holding Lily in his arms and she was floppy and non-responsive”.

His lawyer, Jeremy Morris, described the case as “very sad”, saying his client was “a first-time father who was ill-equipped and too immature to properly care for Lily”.

Family and friends of Lily, including her mother Emma, attended today’s hearing, wearing T-shirts and holding signs with pictures of the baby and displaying the words “Your Life Mattered” and “Light for Lily”.

Previously on this story…

7 News reports, In September 2016, Emma Cosgrove was wearing a T-shirt bearing the face of her dead seven-month-old and the words “I love you mummy”, when the grieving mother screamed “scum” at Paul James Cosgrove, 24, as he pleaded guilty in the Stirling Gardens Magistrates Court to one count of manslaughter.

Ms Cosgrove later told The West Australian that she was “lost without her best friend”.

“Lily is and always will be my best friend,” she said.

“I still ask everyone to pray she’s happy and safe and we will be reunited again when it’s my turn.

“I love and miss her so painfully.”

Last year Cosgrove phoned his wife to tell her that Lily was not well after falling off a change table.

Ms Cosgrove rushed back to their Ellenbrook home. When she found Lily unconscious, she dialled triple-0.

The seven-month-old had swelling on her brain from an injury believed to have been inflicted by Cosgrove hours earlier. She lost her fight for life in hospital two days later.

Cosgrove was charged with aggravated grievous bodily harm but his charge was later upgraded to manslaughter.

Ms Cosgrove said yesterday that she would “never forgive herself” for leaving her only child alone with him.

“Whatever sentence (Cosgrove) gets, my baby will never wake up,” she said outside court.

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Image via 7 NEWS