The trial for Connecticut State Trooper Brian North in the fatal shooting of a 19-year-old began Monday at Milford Superior Court.

North, who pleaded not guilty to first-degree manslaughter with a firearm, is charged with killing Mubarak Soulemane for firing seven gunshots into his stopped car in 2020.

Mark Arons, the attorney for Soulemane's family, said it was a big day for the family after having waited four years for the court processes to start.

Soulemane's mother testified that her son was diagnosed with schizophrenia and bipolar disorder as a young teenager. His sister also said this led to multiple hospitalizations. A woman who said she was dating him in the days leading up to his death stated that his mental state was erratic, paranoid and disorganized.

While Soulemane's family say they are grateful for their chance at justice, supporters of North are looking for justice as well.

"I do think it's a big deal,” said Cathleen Walsh.

Walsh, part of Defend The Police, came to show her support for North. Authorities say North shot Soulemane after the teen had allegedly carjacked a vehicle in Norwalk and led police on a chase on I-95. The chase ended in West Haven when officers boxed in Soulemane. They say Soulemane had allegedly pulled out a knife and was shot by North.

Defense attorney Frank Riccio played multiple recordings Monday, some showing confusion among police moments before Soulemane was shot. Dispatchers involved said they had initially identified the incident as a carjacking, despite one Norwalk official testifying he had called off the chase believing the incident was a theft.

"Part of the total picture that went on that day, they didn't hear it was called off or that it wasn't a carjacking,” said Walsh.

Inspector General Robert Devlin, who investigates uses of deadly force by police, had a different point of view on the first day of the trial. He believes North's use of force was not justified.

"Were you monitoring the broadcast of this officer, who was pursuing this car?” said Devlin.

The judge said the trial is expected to take about a week-and-a-half.

MORE: Family of teen fatally shot by officer in West Haven to file wrongful death lawsuit against state