Grossman was convicted two years ago on two counts of second-degree murder for striking 11-year-old Mark Iskander and 8-year-old Jacob Iskander while they crossed the street with their mother. She is currently serving a 15-year sentence.
During opening statements, the Iskander family's attorney, Brian Panish, showed jurors photos and videos of the boys, along with clips of witnesses who described Grossman and Erickson as street racing before the crash. One witness said, "It was insanely fast," while another said, "They were like a bat out of hell, clearly racing."
Panish also presented an animation of the collision that he said showed both drivers traveling more than 80 mph in a 45-mph zone. He told jurors the pair had been drinking for hours before the crash.
Grossman, a co-founder of the Grossman Burn Foundation, is the primary defendant in the civil case. Although Erickson was charged only with misdemeanor reckless driving, Panish argued he shares responsibility.
"Because Mr. Erickson is racing, and he's in the first lane, he blocks off the boys' ability to escape and they're both hit at 73 miles an hour," Panish said.
He told jurors Erickson fled the scene, later returned but hid in nearby bushes for three hours, and switched the license plates on his Mercedes to mislead investigators. Erickson's attorney disputed that account, saying Erickson did not flee, did not know Grossman had hit the children and that witnesses were mistaken about his speed.
Grossman's attorney told jurors the socialite was not impaired, was not speeding and that the city of Westlake Village failed to address what she described as a dangerous intersection. She also argued that Erickson's driving contributed to the crash.
Grossman was not present in court Friday and is not expected to testify in the civil case. Attorneys said Erickson will take the stand.