WOBURN (CBS) – A trial is underway for the driver in a deadly crash at Sweet Tomatoes pizza shop in Newton as prosecutors allege criminal liability while his defense argues it was simply a car accident.

The victims’ families were hoping Brad Casler would accept a plea deal and avoid the emotional pain of going through a trial. But that didn’t happen and now the trial got underway Thursday in Middlesex Superior Court.

Casler, 56, crashed into Sweet Tomatoes in March 2016, killing 32-year-old Gregory Morin and 57-year-old Eleanor Miele. Seven others were injured.

Casler was charged with two counts of motor vehicle homicide and one count of driving a motor vehicle to endanger. The judge recommended a sentence of two years in jail and three years probation.

But Casler decided not to plead guilty, choosing to move ahead with a trial. Casler’s attorneys say he shouldn’t be held responsible because symptoms from his multiple sclerosis led to the crash.

Brad Casler arrives at Middlesex Superior Court Thursday morning. (WBZ-TV)

Prosecutor Chris Tarrant told jurors in his opening statement how the crash happened “without warning” after Casler was straddling the center line and driving so fast that another driver in the area felt their car shake before impact.

Casler’s attorney, Thomas Gilbin, opened his remarks by saying “there are no winners” in this case.

“Lives have been lost, others have been damaged. And we can’t change that,” Gilbin said, adding that “the definition of an accident is what you need to consider. Car accidents happen. It doesn’t mean a crime has been committed.”

Gilbin told jurors that Casler’s car was out of control, but added that what is up for debate is why. He argued that Casler suffered a medical emergency, causing the crash.

Following opening statements, Casler, jurors, attorneys and the judge went for a visit to Sweet Tomatoes to see the site of the crash.

Upon returning to the courtroom, witnesses who saw the crash took the stand.

Ashley Tang was driving in the area at the time of the crash.

“No signals, no brakes. I just gasped and said ‘Oh my god’ I didn’t know what to do,” Tang said.