Walden (left) was said to have been frustrated at Bowman (right) because the baby wouldn't go to sleep

A daycare worker has pleaded guilty to killing an eight-month-old girl by smothering her with a blanket because she wouldn't go to sleep.

Leah Walden, 24, admitted the murder of little Reese Bowman, at Rocket Tiers Learning Center, Baltimore in May 2017, at a court hearing on Tuesday, wbaltv reports.

Walden was sentenced to 70 years in prison for the horrifying killing by Judge Althea Handy who sobbed as she handed it down.

In heartbreaking scenes, Reese's father Justin Bowman wept as he told the court: 'I will never see my girl take her first steps, hold her, kiss her, comfort her when she's scared, hear her say "I love you". I am devastated.'

Turning to Walden and pointing he said: 'Reese Annette Bowman accomplished more in her short life than this woman ever will.'

Walden tried to explain her actions by saying she had snapped and had not been given appropriate training or assistance for her job.

Assistant State's Attorney Anne Colt Leitess said Walden had told a co-worker, 'Girl, I'm frustrated. I'm sick of this little b****. I hate this little b****. She makes me want to punch her in the face.'

Eight-month-old Reese Bowman was smothered to death by daycare worker Leah Walden in May last year

The baby was being cared for at the daycare alongside her older brother when she was killed

Her parents Justin and Amy have spoken of their heartbreak at her senseless killing

The court heard that Walden returned from lunch and became frustrated that baby Reese would not sleep.

She then slapped her and pinned her down before piling blankets over her face and suffocating her.

Walden initially claimed she had fed the baby and put her in a crib for a nap before coming back 45 minutes later to find the girl unresponsive.

But her argument unraveled after the center's CCTV revealed the truth.

Walden was seen covering the baby with 'excessive blankets for long periods of time'.

She was also filmed covering the child's face with a pillow, violently snatching the baby and slapping her.

CCTV footage played in court showed the baby kicking wildly as the enraged daycare worker smothered her with a blanket.

Reece's parents Amy and Justin Bowman moved out of their home and left their jobs after their daughter's murder - unable to stay in the city and be reminded of the horror crime

The Rocket Tiers Learning Center in Baltimore where the incident took place has since shut down

Judge Handy broke down as she watched the CCTV video of the baby's murder shortly after the young daycare worker entered the court.

Composing herself, she said: 'I'm just reflecting on everything I heard. There are tears everywhere in this courtroom.'

Walden accepted that the murder was premeditated but said: 'There was not a time in my heart that I wanted this to happen.'

Her sister Samantha Carlton told the court: 'She's not a monster. She's not an evil person. She was frustrated.'

Then she turned to the Bowmans and said: 'I'm so sorry. With all my heart, I'm sorry.'

Mr Bowman told the court that Reese's older brother Sawyer also attended the center and was upstairs when she was killed.

Mourners left bouquets of flowers outside the day care center when the murder took place

Hundreds of people gathered for a memorial service in a fire station in Mahanoy City, Pennsylvania to mourn the death of eight-month-old Reese in May last year

Walden spoke of her childcare experience on the daycare's website and said she liked to care for 'babies who love me as much as I love them'

Stanley Bradford, head of Baltimore's homicide unit called the killing 'just evil' in a statement on Tuesday

He said the family had been forced to sell their house, leave their jobs and move away from Baltimore after the murder. It has left them 'devastated'.

An obituary written by Reese's parents, posted shortly after her death read: 'Dearest baby, please know that our greatest blessing was having you.'

'This beautiful, happy, loving child entered the world on September 4, 2016, being the first girl born into the Bowman family in 47 years.

'She had recently began chattering, clapping and crawling. She lit up and laughed every time her brother, Sawyer, was nearby. Taken way too soon from all those who love her, her spirit and memory will remain in our hearts eternally.'

The city's Criminal Investigations Chief Stanley Bradford told the Baltimore Sun how Walden was seen 'violently snatching the child out of the crib with one arm, swinging at the baby as if she was slapping her, and placing pillows over the baby's face.'

He added: 'Watching that video is disturbing. Reese Bowman, in my opinion, was tortured.'

Rocket Tiers was shut down after Reese's death and a crowdfunding campaign to pay for the Bowman's funeral costs raised over $50,000.

In a statement at the time of the incident last year, Baltimore Police said it appeared the baby was awake at the time of the assault.

Stanley Bradford, head of Baltimore's homicide unit, said: 'To me, and all of us who are parents, when we look at something like that, there's no explanation to give.

'It's just evil. I mean what motive is there to treat a baby that way?

'From what I saw, why would you treat an 8-month-old baby, or any child for that matter, in that manner?'

Bradford added: 'Watching that video is disturbing. Reese Bowman, in my opinion, was tortured.'

Her family released a statement saying losing her had caused 'tremendous pain' and said their 'hearts are broken'.

They added: 'No family should ever have to experience the loss of a child under any circumstances.'