Darren Wilson, the white police officer who killed an unarmed black teenager in Ferguson, Missouri, in August, may not face criminal charges, but the justice system that let him off the hook remains very much on trial.

Benjamin Crump, the attorney for the slain teenager’s family, made the case for the prosecution in New Orleans on Tuesday night, addressing a packed auditorium at Dillard University with a fierce indictment of the grand jury process that allowed Wilson to walk away from the deadly incident without being charged.

Crump occasionally sounded outraged or saddened as he spoke about Michael Brown’s death, but his tone was mainly one of disbelief.

“They just gave softball questions to the killer of an unarmed person for four hours,” Crump said, referring to Wilson’s lengthy testimony before the grand jury last month.

“We don’t get grand jury proceedings when they charge us with crimes,” he continued, addressing the largely African-American audience. “Why are the rules always different when it’s our children lying on the ground?”

As he has done in numerous television interviews over the past few weeks, Crump also objected to the unusual way that prosecutors handled the case — presenting all of the available evidence to the grand jury and remaining ostensibly neutral about whether any charges should be brought.

“I know I ain’t the only one who watches ‘Law & Order,’ ” Crump said. “The prosecutor is always trying to get a conviction!”

Speaking without notes, Crump delivered most of his remarks away from the podium, microphone in hand as he paced the stage, often addressing audience members by name: “Attorney Rice,” for Entergy CEO Charles Rice, or “Attorney Washington,” for local civil rights lawyer and activist Tracie Washington.

While Ferguson remained the focal point of the evening, Dillard President Walter Kimbrough said he actually invited Crump to give the university’s annual Revius O. Ortique Jr. Lecture on Law and Society before the August incident, when Crump was still known mainly for his advocacy on behalf of another slain black teenager, Trayvon Martin.

Crump said he felt the same sense of disbelief when he got the first phone call from Martin’s father after his son had been killed by a neighborhood watch volunteer, George Zimmerman, in 2012. “Tracy Martin had this sound of brokenheartedness, this desperation,” Crump said.

He recalled telling Martin’s father to wait a few days, not believing that Zimmerman would get off without being arrested or charged with a crime after having confessed to killing the unarmed teenager in a Florida subdivision.

“We see every day people in our community get arrested and go to jail with no evidence at all, with innuendo,” Crump said. “Someone said you fit a description, someone thought you were there, that’s enough to get you arrested.”