A daughter’s grudge against her relatives over their treatment of her ailing mother and their handling of a family property dispute prompted her to shoot her uncle and aunt dead with a handgun in a public park three years ago, a Hong Kong court heard on Wednesday.

Ada Tsim Sum-kit shot Jim Siu-fan, 80, and Chim Chun-ki, 62, in the head from a short distance in Quarry Bay Park on June 26, 2018, a prosecutor told a jury on the first day of the trial.

Another uncle, Jim Chin-kui, and aunt, Jim Siu-wai, were also caught up in the fatal shooting, with a bullet hitting the former in the arm and grazing the latter on her shoulder, senior assistant director of public prosecutions Derek Lai Kim-wah said.

The pistol allegedly used in the crime.

“She fired four shots at a close distance. Each of the shots hit the two uncles and two aunts,” the prosecutor said, adding that police later found five remaining bullets in her 25 calibre weapon. They also found 41 additional rounds of ammunition on her.

But the prosecutors stopped short of shedding light on how Tsim obtained the firearm and ammunition.

The 47-year-old woman has pleaded not guilty to two counts of murder and two further counts of shooting with intent to cause grievous bodily harm. Her lawyer is expected to argue that her mental condition had impaired her judgment at the time of the attack.

Setting out the allegations on Wednesday, the prosecutor said Tsim had been unhappy about a decision by her seven uncles and aunts to place her mother in a home for the elderly after her health deteriorated in 2013 – even though she agreed to it.

Following her mother’s death in 2015, Tsim began to quarrel with her relatives over a property left behind by her grandmother at Nam Fung Sun Chuen in Quarry Bay, Lai said. She accused them of being greedy, depriving her mother of a share of the property. At one point, she created a web page to set out her allegations against them, which prompted the relatives to make an inquiry.

Flowers are laid for the victims of the shooting at Quarry Bay Park.

Tsim offered to take the website down. But despite her promise, Lai argued: “Deep down, the defendant still harboured ill feelings for [her mother’s] siblings.”

Lai said that about a year before the shooting the siblings came up with a way to sell the property and promised to give Tsim back her share. But she missed a meeting with several of the relatives on June 15, 2018, about a week before the shooting.

Days later, she texted them to apologise for her absence and arranged a meeting for June 26, saying she wanted to thank them for what they had done for her mother. The four victims attended the event, together with Tsim’s older brother.

The prosecutor said they went for lunch together the day before Tsim suggested they should go to Quarry Bay Park. She pulled out the gun and fired at the four, the prosecutor said. Her older brother ran away and escaped being shot.

Tsim was subdued by security guards when she fled to nearby Cityplaza before police arrived at the scene.

Officers said Tsim told them she shot them because of “enmity” between her and her family. But she later clarified she did not say “enmity” but “dispute”.

Testifying on Wednesday, Jim, the uncle who was shot in the arm, said he found it odd that Tsim took issue with sending her mother to an elderly care home because she was involved in selecting it. She also never paid any fees, he said.

He also recalled that shortly before the mother died, he told her not to worry about her children and promised to give between HK$200,000 (US$25,760) and HK$300,000 after selling the Quarry Bay flat. He said Tsim was present at the time.

Seven female jurors are expected to return a verdict at the end of trial, which is likely to run 13 days.

The woman, last seen with a boyish short cut, sported long locks tied to the back of her head on Wednesday. She squinted and stared into the distance from the dock as she heard the allegations read before her.

The prosecutor said Tsim was born in the northeastern Chinese city of Tianjin in 1973 and grew up in a public housing estate with her family of four including her father, who died in 2005, and older brother. She believed that her older brother had also cheated her mother over the Quarry Bay property.