It was a day before her birthday and five days before her wedding anniversary.

But the mother of two was depressed, exhausted and having troubles in her marriage.

She decided that her autistic seven-year-old son was the cause of her tiredness and problems and that he had to go.

On Sept 13, 2014, she got him to stand on a stool by the kitchen window of their Tampines flat and pushed him out.

The boy fell nine storeys to his death.

Yesterday, the 43-year-old mother was jailed five years for one count of culpable homicide not amounting to murder.

The court heard that while the woman was found to be of a sound mind then, she had been suffering from major depressive disorder that impaired her mental responsibility and actions.

Neither she nor her son can be named due to a gag order issued in 2014.

Court papers said the mother was having a "cold war" with her husband on the day of the incident.

Tensions escalated when she shouted for him to bring in the aluminium laundry poles hung outside the kitchen window as it was raining.

Her husband did so, but threw the poles, together with the clothes, onto the kitchen floor, before taking their older son, now 14, to a tuition class.

He left just after 11.30am.

As his wife was clearing the mess on the kitchen floor, she noticed neighbours from the opposite block staring at her and she made a rude gesture at them.

She then placed a stool at the kitchen window so that she could look out for the missing aluminium poles that had fallen off in the heavy rain.

But she stopped herself when she felt dizzy and took a shower to freshen up.

After coming out of the shower, she saw that her younger son had defecated in his pants and fallen asleep on the sofa with the television set still turned on.

DIFFICULTIES

Court papers said the boy was diagnosed with autism spectrum disorder, characterised by speech and language impairment, difficulties in socialising as well as repetitive behaviours and unusual interests.

After cleaning her son's pants, the woman went into her bedroom to rest, but came back out when she heard noises in her kitchen.

When she went to check, she saw her younger son and was suddenly seized by the thought that he was the reason for her exhaustion and martial problems.

She decided to kill him and noticed the stool still by the kitchen window.

She coaxed her son to stand on the stool and told him to look downwards to search for his grandmother.

The boy obeyed.

She then grabbed his calves and pushed him out of the window.

The incident was witnessed by an Indonesian maid at a neighbouring block, court papers said.

Police received a call for assistance at about 1pm and officers found the boy lying motionless at the bottom of the block.

Neighbours pointed them to the accused's ninth-storey unit.

Officers found the mother, who opened the door while hugging a pillow, in a daze and her eyes closed.

When informed that they were investigating a fall from height, she fell to the ground, began crying and became hysterical.

She was arrested and charged with murder two days later.

The charge was later amended to one of culpable homicide, which she pleaded guilty to yesterday.

Deputy Public Prosecutor Krystle Chiang said in her submissions yesterday that this was a tragic case and that the boy's life was prematurely ended.

She noted the mother's mental condition, but said it should not be a blanket excuse for every aspect of the criminal conduct.

Defence counsel Anand Nalachandran said in mitigation that his client's husband and remaining son had written letters, saying they would like to be reunited with her.

He also said that his client had always put her family before her own needs and had felt the strain as the primary caregiver of her dead son.

TEARS

The accused, who appeared calm for most of the hearing, was seen tearing at this point.

Justice Tay Yong Kwang noted that the accused had a mental history condition since 2008 and that doctors said she was at a low risk of committing violent crimes in future.

Court papers also said that her condition improved significantly after she was put on anti-depressant and given psychiatric treatment in prison.

Justice Tay said: "I hope you can recover well and return home to your family much stronger emotionally, and rebuild your family and personal life."

No one answered the door when The New Paper visited the flat yesterday.

An immediate neighbour said the family has moved out and are renting out the flat.

"The husband and his son came back a few days after the incident to pack. That was the last I saw of them," the neighbour said.

She also said that she tried consoling the mother on the day of the incident.

"I went over to comfort her as she was crying and crying, but I had no idea then that it was she who did it," said the neighbour.

"I feel so sad for the boy. His life was gone just like that."