A woman told a Saskatchewan court today that she saw Gerald Stanley shoot Colten Boushie while he was sitting in an SUV on Stanley's farm.

"He shot Colten in the head," said Belinda Jackson, who was one of the four young people with Boushie the night he was killed.

Boushie, 22, who lived on the Red Pheasant First Nation reserve, died on Aug. 9, 2016, after an SUV carrying five young people drove up the driveway on the Stanley farm.

Stanley, 56, is now on trial on a second-degree murder charge in Court of Queen's Bench in front of a jury in Battleford, Sask. He has pleaded not guilty.

Jackson, 24, said during day three of the trial she heard Stanley tell a younger man — previously identified in court as Stanley's son Sheldon — to "go get a gun" before Boushie was shot.

She said Sheldon emerged from the farmhouse with a long gun in his hands while his father went into a garage, came out with a handgun and went to the SUV and fired two shots at Boushie's head.

An autopsy report summarized at the start of today's proceedings by Crown prosecutor Bill Burge said there was only one bullet hole in Boushie's head.

After Jackson testified about what she remembered from that day, she was challenged by Stanley's attorney, Scott Spencer.

"I don't believe you're telling the truth," he told the woman.

Recognized Stanley later by photo

Jackson testified that she had been drinking on the day Boushie died.

She said she did not know who Stanley was that day but later recognized him as the shooter when she saw his photo.

"I saw his picture and I started remembering things," she said.

Belinda Jackson, who was in the back seat of the SUV when Colten Boushie was shot, identified Gerald Stanley as Boushie's shooter. (Don Somers/CBC)

Earlier this week, Sheldon Stanley said both he and his father were on the farm that day.

Sheldon testified he went into the house to retrieve his truck keys after the SUV pulled into the family's driveway and a man got out of the vehicle and tried to start an ATV parked on the property.

He said his father told him the gun believed to have killed Boushie went off accidentally.

But Greg Williams, an RCMP forensics firearms expert testified on Thursday that tests showed the gun couldn't be fired without pulling the trigger.

Jackson's testimony also contradicted Sheldon's when she denied picking up the rifle barrel that was found near Boushie's body. Sheldon testified yesterday that Jackson and the other woman who had been in the SUV, Boushie's girlfriend Kiora Wuttunee, were "pointing [it] at each other and saying, 'Bang, Bang.'"

They did agree on one point: Jackson did attack Sheldon's mother and Gerald Stanley's wife Leesa who, by the time of the shooting, was also at the SUV.

"I punched her," said Jackson of the aftermath of the shooting.

Firearms expert Greg Williams said the gun that killed Colten Boushie could not have been fired without pulling the trigger. (Cloudesley Rook-Hobbs)

'Bullet right beside my ear'

Earlier on Thursday, the person who drove Boushie and others onto the farm, 18-year-old Cassidy Cross-Whitstone, told jurors he heard bullets whizzing past him as he tried to run from the farm.

He said he took off when someone smashed the SUV's windshield after another passenger, Eric Meechance, tried to steal the ATV.

"I heard a bullet right beside my ear," he said. "I can hear that stuck in my head."

When he was cross-examined by Spencer, Cross-Whitstone said he originally told police he believed warning shots were being fired in the air.

Spencer said Cross-Whitsone lied about trying to break into a truck on a neighbouring property before the group reached the Stanley yard.

"I was scared for myself and the people that might get in trouble," he said.

Cross-Whitstone said he was under a driving ban and was "pretty hammered" on the day of Boushie's death.

Cassidy Cross-Whitstone, the person who was driving the SUV that brought Colten Boushie to Gerald Stanley's farm, arrives at the courthouse. (Guy Quenneville/CBC)

Boushie's blood alcohol content was 0.3 per cent when he died, according to a summary of toxicology tests presented by Burge.

For comparison, Saskatchewan's legal driving limit is 0.04 per cent.

"Colten Boushie is not on trial here," said Boushie's cousin Jade Tootoosis outside the courtroom. "Those four other youth are not on trial here. Gerald Stanley is."