A jury in Grand Rapids, Mich., began hearing testimony on Monday in the murder trial of a white former police officer who fatally shot a Black man as the two scuffled on the ground after a traffic stop in 2022.

There is no dispute about the basic sequence of events that began as the officer, Christopher Schurr, pulled over a Nissan Altima for an improper license plate in a residential area on a cold, rainy morning.

After the driver, Patrick Lyoya, got out of the vehicle, he and Mr. Schurr got into a physical confrontation and tussled on the ground over control of the officer’s stun gun. In a video filmed by a bystander, Mr. Schurr could be seen struggling to pin down Mr. Lyoya before the officer reached for his firearm and shot him at close range.

Jurors must decide whether Mr. Schurr’s use of deadly force amounts to second-degree murder.

In opening statements on Monday, Chris Becker, the Kent County prosecutor, told jurors that the shooting “was not justified” because the Taser that the two men were grappling over did not pose a dire threat to the officer. While Mr. Lyoya resisted being arrested, Mr. Becker said there was no evidence that he intended to seriously harm Mr. Schurr.

But Mikayla S. Hamilton, one of Mr. Schurr’s lawyers, said he opened fire after losing control of the Taser, which made him fear that he was “in a fight for his life.” She added: “This was not murder, this was survival, this was self-defense.”

Mr. Lyoya’s fatal shooting on April 4, 2022, took place amid national debate over police misconduct and racism set off by the killing of George Floyd in 2020. Mr. Lyoya’s death led to protests in Grand Rapids, a city of about 200,000 where nearly 18 percent of residents are Black and where the case strained longstanding tensions over race and the police.