Not long after his father told him the semi-automatic pistol he was holding accidentally went off and killed Colten Boushie, Sheldon Stanley — the son of Boushie's accused killer Gerald Stanley — said he and his parents sat in silence drinking coffee around their dining room table.

It was a brief period of quiet before police arrived at the farm near Biggar, Sask., and an investigation began into the fatal shooting of Boushie, 22, from the Red Pheasant First Nation, who had driven onto the Stanley cattle farm on Aug. 9, 2016, with four other people — two men and two women.

"I don't know what happened. It just went off. I just wanted to scare them," Sheldon remembers his father saying after three shots were fired from the pistol.

The younger Stanley testified at his father's trial today in Court of Queen's Bench in Battleford, Sask. Gerald Stanley, 56, has pleaded not guilty to second-degree murder in Boushie's death.

Sheldon, 28, said he and his father were working on a fence on the afternoon of Aug. 9, 2016, when they noticed an SUV loudly coming down the driveway toward their home and shop.

Sheldon Stanley, son of accused killer Gerald Stanley, walks outside the courtroom in Battleford, Sask., following his testimony. (Chanss Lagaden/CBC)

When one of the passengers got out and started an ATV near the shop, Sheldon told the jury that he began running toward the man.

He said the man got back into the SUV, which then backed into a vehicle belonging to Sheldon's mother.

3 gunshots

Sheldon said he was heading into the farmhouse to get his truck keys, when he heard the first gunshot, followed by two more.

He testified that he saw his father standing by the side of the grey Ford Escape and a man in the driver's seat was slumped over the steering wheel.

The RCMP shot this aerial view of the Stanley property and the long driveway leading to it. (RCMP)

He said his father, looking sick, walked toward him with the pistol in one hand and a magazine in the other.

Sheldon said two women who had been in the backseat of the SUV got out and opened the front driver's door after the shooting. The two women have since been identified as Kiora Wuttunee and Belinda Jackson, and both are expected to testify tomorrow.

As Boushie tumbled halfway out of the SUV, a loaded rifle barrel later found at the scene by the RCMP near Boushie's body "was laying between his legs and as they pulled him, it came out with him," the younger Stanley testified.

Later the women attacked Sheldon's mother Leesa, he told the court.

Boushie's body fell partly out of the car and was fully pulled out by two female passengers, according to Sheldon Stanley. (RCMP)

"They had her on the ground and were hitting her," Sheldon said. "So I broke into a run, yelling them to get off of her."

They did and went back into the SUV, he said.

He said the women later got out again and picked up the rifle barrel.

"They were almost mocking what had happened, pointing at each other and saying, 'Bang, Bang.'"

Sheldon's testimony came after the court heard from RCMP Const. Andrew Park, who testified about the investigation, including a complaint police received about people in a grey SUV trying to break into a truck about 20 kilometres from the Stanley farm on the same day Boushie was shot.

SUV passenger testifies

Another passenger in the SUV, Eric Meechance, followed Sheldon's testimony Wednesday.

Meechance, 22, said the five passengers — the fifth being Cassidy Cross — began their day drinking whisky, listening to music and shooting targets with the fully intact rifle in the backyard of Boushie's grandmother on the Red Pheasant First Nation reserve, located about 57 kilometres north of Biggar.

Eric Meechance, shown in this courtroom sketch, was the first of the four surviving SUV passengers to testify Wednesday. The other three are expected to speak Thursday. (Cloudesley Rook-Hobbs)

After a swimming trip off the reserve, the group got a flat tire while riding in Wuttunee's SUV, he told the court.

He said they continued driving and stopped at one farm where Cross broke the stock of a .22 calibre rifle that was in the vehicle trying to smash the window of a truck. They later drove on to the Stanley farm near Biggar, Sask., and were on an all-terrain vehicle but took off when someone started yelling at them, he said.

Meechance said he fled the car. He said Wednesday that he heard two bullets whiz past him as he ran down the driveway toward the main road, but didn't see what happened to Boushie.

The 22-year-old broke down in tears in court when forced to examine a photo of Boushie's body.

"How come you have to have that body laying in front of that thing like that?" he said when asked to look at a photo of the barrel of a .22 calibre rifle that was near Boushie's body.

Meechance said he thought the gun in the SUV wasn't loaded, and that he hadn't told the police about it because he had a gun ban.