State prosecutors took their own case to trial on Monday against three former Memphis Police Department officers who fatally beat Tyre Nichols, aiming to secure a murder conviction after jurors in a separate federal case delivered a mixed verdict last fall.

In many ways, the state trial will resemble the one that played out in federal court: It will focus heavily on surveillance and body camera footage that captured the officers beating Mr. Nichols after he tried to flee a traffic stop on foot in January 2023. The trial will also consider whether the three defendants acted in accordance with their police training.

But on the first day of proceedings in a stuffy Memphis courtroom, there were some notable differences, including testimony from Mr. Nichols’s mother, RowVaughn Wells.

“My son was beaten to a pulp,” Ms. Wells said, her voice shaking with emotion as she described his injuries at the hands of the officers. “There is no way my son would have survived from that,” she added.

The three men on trial Monday — Tadarrius Bean, Demetrius Haley and Justin Smith — already face the possibility of years in prison after they were convicted on federal witness tampering charges in October. Mr. Haley was also found guilty of violating Mr. Nichols’s civil rights by causing bodily injury, though all three men were acquitted of the most serious charge, violating civil rights by causing death.

Tadarrius Bean, left, and Justin Smith Jr. already face the possibility of years in prison after they were convicted on federal witness tampering charges last year. Credit…Chris Day/Pool, Commercial Appeal/USA Today Network, via Associated Press