More than three years ago, a Los Angeles socialite allegedly fatally struck two young boys as they were crossing the street. Now a jury will decide whether Rebecca Grossman is guilty of second-degree murder, vehicular manslaughter and hit-and-run driving.

This week jurors heard opening statements in the long-awaited trial of Grossman for the deaths of brothers Mark Iskander, 11, and Jacob Iskander, eight.

Prosecutors have said that the 60-year-old was speeding in her Mercedes when she struck the boys as they were walking along a crosswalk with their parents. She allegedly drove another quarter-mile before her engine came to a stop, the LA county district attorney’s office said.

Tony Buzbee, Grossman’s attorney, has said that his client was not speeding and that another driver hit the children first. Grossman, who is a cofounder of the Grossman Burn Foundation alongside her husband Dr Peter Grossman, has pleaded not guilty.

The accident took place in Westlake Village, about 40 miles (64.37km) from downtown Los Angeles, on 29 September 2020. The Iskander boys and their brother, who were on rollerblades, a skateboard and a scooter, were on a walk with their family on Triunfo Canyon Road when they began to cross at a marked crosswalk that evening.

Grossman was driving behind Scott Erickson, a retired Dodgers pitcher who prosecutors said Grossman had been drinking with at a nearby restaurant. The pair were reportedly in a romantic relationship at the time.

Witnesses said that Erickson, who they described as speeding, swerved around the family while Grossman briefly braked but struck them and continued down the road.

A collision investigator testified in a preliminary hearing that 1.5 seconds before the crash, Grossman was driving at 81mph before breaking to 73mph, far over the speed limit of 45mph, the Los Angeles Times reported.

Mark died at the scene, his body found more than 250ft away from the crosswalk. Jacob, who was thrown as far as 70ft, later died in a hospital.

Erickson was later charged with misdemeanor reckless driving in relation to the incident.

Grossman’s blood alcohol levels were not above the legal limit, but in the trial’s opening statements on Friday, prosecutors said that she was “impaired with alcohol and Valium”.

Ryan Gould, the deputy district attorney, described the scene from the perspective of the boys’s mother, Nancy Iskander. She heard “the deafening sound of cars barreling down on her” and when she realized they weren’t slowing, she tried to bring her children to safety, Patch reported.

“She grabs her youngest son, Zachary, and dives out of the way of the black SUV. She’s able to save Zachary and when she looks back and sees the white SUV going through the intersection, her children are no longer there,” Gould said.

Buzbee, Grossman’s defense attorney, has said that the case was “negligently handled” and described it as “malicious prosecution”.

“She was not impaired, she was not racing, she was not going the speed that they claim and she never fled the scene,” he said on a website created by Grossman’s daughter.

Buzbee has said that Erickson hit the boys first, and stated this week that experts will testify that other vehicles hit the children and that Grossman was not the first nor the last.

Grossman faces up to 34 years to life in prison.