A six-year-old boy from New York was beaten to death after being subjected to months of torture by his mother's boyfriend according to horrific details outlined in court on Monday.

The Manhattan Supreme Court on Monday heard how Zymere Perkins was eventually beaten with a broken broomstick and a shower rod before being hung on the back of a bathroom door and left to die in a roach and maggot-infested apartment in Harlem.

Assistant District Attorney Kerry O'Connell told jurors Rysheim Smith allegedly killed his girlfriend Geraldine Perkins's son in a fit of anger.

The trial of Rysheim Smith for the murder of six-year-old Zymere Perkins began on Monday

Zymere Perkins died in September 2016 after what prosecutors say was months of abuse by his mother and her boyfriend in their feces and roach-infested Harlem apartment

Rysheim Smith allegedly killed his girlfriend's son, Zymere, by beating him with a shower rod and then hanging him by his t-shirt on the back of the bathroom door

His mother, Geraldine Perkins, carried her son to hospital but is alleged to have waited so long there was no hope of saving the unconscious youngster

'He picked up Zymere, held him by the arm and began to beat him with a stick like a piñata,' she said.

'Tellingly, he did not call out to his mother… because he knew his mother was not going to protect him.'

Smith became enraged with the youngster who was constantly wetting his makeshift bed and who also once defecated in the living room and then tried to hide his own feces.

According to the Daily News, District Attorney O'Connell explained how Smith after beating the boy, 'waterboarded him in the shower' before dropping him onto the floor and beating him with a shower rod cutting his head.

Zymere lost consciousness and collapsed in the bathtub.

He is alleged to have finally hung him on the back of the bathroom door by his t-shirt after he lost consciousness.

O’Connell said this was likely 'where he took his last breath'.

Eventually, Smith lifted Zymere off the hook and threw him against a bedroom wall, where he fell to the floor, she alleged.

His own mother who is alleged to have watched on 'passively' as the abuse took place, is said to have waited several hours before checking on her son after the beating. When she finally did so, he was already dead.

Perkins carried his body from their 135th Street Harlem home to the hospital long after he could be saved.

Smith, meanwhile, left the apartment to go and get food.

Graphic photos of Zymere's badly beaten body were shown to jurors which detailed his injuries including cuts and bruises to his neck, head and ribs.

On Monday, ER nurse Michael Nelson recalled how Perkins ran inside the hospital 'screaming' as she carried Zymere in her arms.

'He was extremely cold. I felt the coldness of him through his clothes,' he said. 'This child was dead for a while. There was no bringing this child back.'

Geraldine Perkins, and her boyfriend, Rysheim Smith, were arrested soon after the boy's death. Perkins has claimed that Smith dealt the deadly blows to the child that led to his death

O'Connell went onto portray how unpleasant life had become for Zymere in his home where flies had laid eggs in feces that was embedded into the carpet and crawling with maggots.

Zymere was allegedly 'deprived of food as punishment' and given just bread for dinner while his mother and her boyfriend feasted according to the prosecutor.

'When he was caught eating from the garbage because he was so hungry, the defendant beat him mercilessly,' O'Connell said. 'He had broken ribs on broken ribs. This child had more fractures than he had ribs.'

The boy's chest and belly were covered in scratches, scars, and bruises.

Perkins, 28, pleaded guilty to second-degree manslaughter in 2017 and has already been behind bars for three years. She is expected to receive between two and six years for her testimony against Smith.

Smith is pictured in court when was initially charged in 2016

Smith, is alleged to have begun beating Zymere very early in the couple's relationship and encouraged her to 'emulate' the violence under the guise of 'discipline', although the New York Post reports how the abuse went on for more than a year.

'Zymere was disciplined by Rysheim Smith because he thought it would make a man out of a boy,' O'Connell said. 'She put a man's importance to her ahead of the life and welfare of her child.'

O’Donnell said Smith completely dominated Perkins and prioritized her relationship with her boyfriend before that of her own son.

After Zymere's death, three Administration for Child Services employees were fired from the troubled agency. Its commissioner, Gladys Carrion also resigned.

It was revealed that up to five welfare reports were filed on Zymere's behalf but were ignored. An investigation into allegations of severe corporal punishment was also closed.

The failings of the agency will also be revealed in court during the trial. ACS received a tip-off in 2015 that alleged Smith smacked Zymere 20 times at a picnic.

The little boy also told ACS workers how his mother's boyfriend hit him and punished him by forcing him to take cold showers.

Smith's defense attorney, Heather Smith, has said the death of Zymere is solely down to Perkins who she described as a 'profoundly unreliable person who will say anything to avoid jail time.'

'There is no reliable evidence that Rysheim's actions caused Zymere's death,' she said. 'Perkins is a known liar with every incentive to lie to save her own life.'

Smith faces up to life in prison if convicted of second-degree murder, manslaughter and other charges.

At the time of the little boy's death, city officials acknowledged that Perkins, was investigated five times for abuse allegations.