As he wiped away tears, Chun Qi Jiang told his trial it was also his mother's idea to chop up the body of his on-again-off-again girlfriend, Guang Hua Liu, after it was clear she was dead.
The testimony heard by a jury in a Brampton, Ont., court followed an admission from Jiang a day earlier that he had helped dispose of Liu's remains and lied to police, although he denied murdering or dismembering the 41-year-old.
Jiang didn't call police or an ambulance after the gruesome incident that took place in the basement of his home, court heard.
"I was not thinking properly at that time," he said through a Mandarin interpreter. "I only know that I must protect my mother."
WARNING: SOME DETAILS OF THIS STORY MAY DISTURB SOME READERS
Jiang was arrested on Aug. 26, 2012, and originally charged with second-degree murder in Liu's death. The charge was upgraded to first-degree murder last summer.
Liu's mother died shortly after Jiang's arrest. Her death wasn't considered suspicious.
Crown prosecutors have alleged Jiang was unhappy with Liu for reconciling with a new boyfriend. They allege Jiang killed Liu in his home before cutting up her body and disposing of her remains.
But Jiang's testimony Tuesday, under questioning from his defence lawyer, suggested a different story.
A big bone of contention between Jiang's mother and Liu, court heard, was the theft of some jewelry, which Jiang's mother believed Liu had stolen from her in the past.
Jiang told the court that in the days before her death he thought he was rekindling his relationship with Liu, but noted he wanted Liu to address the jewelry issue with his mother.
On the day she died, Liu and Jiang decided to have dinner at Jiang's house at Liu's suggestion.
Jiang warned Liu that the meal would have to be a quick one because his mother, who stayed with him from Friday to Sunday every week, was at home but was sleeping, court heard.
It was that meal, which Jiang's mother walked in on, which set in motion a series of events which led to Liu's death, court heard.
"She said 'Why are you here again, why are you in my home again? You stole my stuff,'" Jiang recounted.
The two women got into a confrontation which resulted in Liu grabbing a kitchen knife as Jiang's mother backed her up against a kitchen sink.
Jiang stepped between the two women and was struck in the head with the knife before he was able to get Liu to drop it, he said. At that point Liu and Jiang's mother left the kitchen, he said, while he tried to wash the gash on his head in the sink.
The court heard that Jiang then tried to find bandages for his wound before going in search of his mother, whose help he wanted in dealing with the cut.
When asked if he heard any noises during this time, Jiang repeatedly said he didn't.
After checking the home's upper levels, Jiang descended into the basement where he discovered his mother in a dark room, leaning over Liu's bloody and lifeless body, he told the court.
"I saw that she has a knife and she was striking Ms. Liu's head," Jiang said, putting his head in his hand.
"I did not hear my mother utter any noise and Ms. Liu, at least the person who was lying on the floor, did not have any sound and there was no movement."
Jiang told his trial he didn't initially know how to react, but eventually knelt down beside his mother and wrapped his arms around her.
"I had both her hands inside my arms and my mouth was pressed on my mother's ear. And I said to her, 'Mother it's all right. I'm your son. I will love you always.'"
The trial has heard from the Crown that Liu's head showed more than 40 "chop-like" wounds caused by a sharp-edged object.
Jiang told the court he checked to see if Liu was breathing and searched for her pulse, but it was clear she was dead.
"I knew that she was beyond any rescue," he said, adding that he and his mother covered Liu's body with a blanket and left the basement.
"At that time my mother looked very tired and even for me it seemed that my life came to an end," he said.
Later that night, when considering what to do with Liu's body, Jiang said it was his mother who suggested dismemberment.
"My mother said the only way is to cut her up and we dispose of the pieces," he said, recalling that he followed his mother back down into the basement. "My mother told me to go away and she closed the door."
Court heard that Jiang's mother carved up Liu's body, brought up parts of her remains to wash them in the kitchen sink, and then packed them in plastic bags.
At one point in an effort to assist his mother, Jiang said he put Liu's torso into a suitcase. He also went thorough the contents of her purse, cut up her cards and put her personal belongings in bags to be disposed off with her remains.
All traces of Liu were loaded into Jiang's car sometime after midnight so mother and son could leave to dispose of her remains, court heard.
Liu's foot was found in Mississauga's Credit River on Aug. 15, triggering a massive investigation. Her head was discovered the next day in the same river, wrapped in grocery bags.
Jiang's testimony continues on Wednesday.