Kulwinder Kaur Bahia, 23, allegedly stabbed her mother-in-law 16 times with an eight-inch kitchen knife, her sister-in-law 46 times, and her four-year-old nephew 11 times. She is alleged to have then doused the house in petrol and set it alight.
David Crigman QC, for the prosecution, told Northampton Crown Court that Bahia came to Britain from India at the age of five. In February 1989, when she was 18 years old, she entered an arranged marriage.
She lived with her husband and his mother and other members of the family in Bowden Road, Smethwick, West Midlands, and gave birth to two daughters. Across the road lived one of her husband's sisters, who had a son aged four.
Mr Crigman said family life deteriorated, with Bahia claiming she was ill-treated by both her husband and her mother-in-law who complained about her behaviour and beat her. The family was said to have been very disappointed that her second child was not a boy, and there was talk of a divorce.
Mr Crigman said Bahia became very unhappy and by 5 November 1992 she had formulated a plan to kill. He told the court that on 7 November, she returned home from her job as a machinist, collected the knife and went to the home of her sister-in-law whom she stabbed in a frenzied attack. She then attacked the woman's son, stabbing him repeatedly.
Bahia denies murdering her mother-in-law, Gurmej Kaur Bahia, 60, her sister-in-law Surinder Kaur Dhandwar, 28, and Avtar Singh Dhandwar, 4. She also denies the attempted murder of a four-month- old child.
Mr Crigman said Bahia left the bodies on the kitchen floor and returned to her own home to change her clothes, which would have been covered in blood. She awaited the return of her husband, who had a bath and went to the pub.
The court was told that Bahia attacked her mother-in-law, stabbing her repeatedly in the back, shoulders, chest and neck.
The prosecution says she then put her mother-in-law's body into a large plastic bag and dragged it across the road to her sister-in-law's house. She poured petrol in the kitchen, the lounge and upstairs bedrooms and set it alight.
Mr Crigman said lawyers representing Bahia would contend that she was not guilty of murder but guilty of manslaughter on the grounds of diminished responsibility. It was accepted that she caused the deaths.
Mr Crigman said two days after the discovery of the bodies, Bahia allegedly attacked a four-month-old child by swinging it against a wall, causing a fractured skull.
The trial continues.