In the trial of Rose, the activist said that after a vigil, a Ferguson police officer told him to wait on a parking lot while police cleared the street. Moments later, he said, he saw an officer from an unknown department point at him, then St. Louis County Police put him in handcuffs.

A Ferguson officer testified he remembered seeing Rose among the protesters. But no witness remembered seeing defendants in two other trials.

Judge Dueker has yet to rule in the four trials. But in the most recent two trials, he pointed to a lack of evidence. He said the prosecutor’s cases seemed to hinge on the belief that because the defendants had been arrested, they must be guilty.

Chassaing acknowledged the cases were circumstantial, but said the judge should convict the defendants. The judge, he said, could infer that because officers took the defendants into custody, they had been among 11 protesters disregarding police orders to stay out of the street.

As the courtroom emptied one afternoon, Chassaing noted that lawyers can’t choose the facts in their cases.

But they can choose whether to prosecute, others say.