They denied the charges at the Old Bailey court in London.
Prosecutor Richard Whittam told the jury that the suspects deliberately attacked an unarmed man from behind using a vehicle as a weapon “and then they murdered him and mutilated his body with a meat cleaver and knives.”
Rigby, who was married with a young son, was killed on May 22 outside the Woolwich Barracks in southeast London.
Describing the events of that day, the prosecutor said the two suspects drove at Rigby in a car traveling at 30 to 40 miles per hour. The soldier appears to have been knocked unconscious by the impact, he said.
The court was shown surveillance video of the car crossing to the wrong side of the road before it hit him, and Rigby rolling onto the hood of the car. He was carried on to the sidewalk.
Footage from a different surveillance camera showed two men dragging the soldier’s limp body from the sidewalk into the middle of the road. Cars driven by passersby stopped at the scene, some with their warning lights flashing.
Whittam, the prosecutor, said the men were armed with a meat cleaver, knives and a revolver when they got out of the car.
“They both attacked the motionless body of Lee Rigby. He was repeatedly stabbed, and Michael Adebolajo made a serious and almost successful attempt to decapitate him with multiple blows to his neck with the meat cleaver,” he said.
“Michael Adebowale was using a knife to stab and cut at Lee Rigby’s body.”
Whittam said the two men dragged the soldier into the road so members of the public could “see the consequences of their barbarous acts.”
At this point, he said, some of the people present showed a “bravery and decency” in stark contrast to the suspects’ alleged acts.
One woman stroked Rigby’s body in a gesture of comfort, he said, while another engaged Adebolajo in conversation despite the fact that he was still holding the meat cleaver in his blood-covered hands.
When police arrived at the scene, the two men moved toward their vehicle, Whittam said.
Adebolajo carried the cleaver, while Adebowale held the firearm. He aimed it at the officers, although it was not loaded, the prosecutor said.
Both men were shot and detained, and the firearms officers gave first aid to keep them alive, he said.
The two suspects are accused of waiting for police to reach the scene, having conspired together to attack an officer. “It is clear that there was an agreement to attack the police when they arrived,” Whittam said.
Adebolajo got “very close” to the driver’s side of the police vehicle, he said. While the gun carried by Adebowale was not loaded, he also had on him the knife he’d used to attack Rigby, the prosecutor told the court.
Whittam said the attack unfolded in a very public place, near a school.
Friends and family of Rigby were in court Friday for the opening of the trial.
Some family members left the court crying as images were shown of the soldier before the attack, as he left the public transit system in Woolwich.
Adebolajo has asked to be known as Mujaahid Abu Hamza in court, and Adebowale as Ismail Ibn Abdullah. However, the court has continued to use their given names.
The jury was told both men have pleaded guilty to a charge of possession of a firearm with intent to cause fear of violence.