Since Hanover police prosecutor Mariana Pastore isn’t talking, it’s hard to figure out how she decided to file criminal trespass charges against some people but not others who were on the Dartmouth Green during a pro-Palestinian protest back in May.

Did Pastore review arrest reports? Did she watch police videos of the protest? Did Dartmouth hand her a list of student-activists that it considers bad apples?

Did she flip a coin?

It’s anyone’s guess.

All the public knows for sure is that 55 people have been charged with criminal trespass, some of whom weren’t even participating in the demonstration but still got caught up in the police dragnet.

As for the 34 others who were handcuffed, arrested and hauled away to area police stations in Dartmouth Outing Club vans that night, their cases have been deep-sixed.

This week, I asked Pastore how she decided which cases to pursue. She wasn’t forthcoming. “I don’t discuss pending cases with the media,” she told me via email.

Pastore has been mum from the outset, so at least she’s consistent. But that doesn’t do much for building public trust. It’s also a stark reminder of the power that prosecutors possess in our society. After police make an arrest — which can be entirely arbitrary, as the peaceful protest on the Green showed — it’s left to a prosecutor to determine whether a case has merit.

As someone who was on the Green on May 1, I didn’t see a reason for anyone to be arrested or charged with a crime. People who exercise their constitutional rights in a nonviolent manner shouldn’t be treated as criminals.

Evidently, Dartmouth President Sian Leah Beilock and her lieutenants disagree, or they wouldn’t have invited police — many dressed in riot gear — onto campus.

In a majority of the 89 cases, Pastore sided with Dartmouth.

The public deserves to know where Pastore drew her dividing line. Did she toss out some cases because police used excessive force?

The case of Dartmouth history professor Annelise Orleck comes immediately to mind.

Orleck, 65, went to the Green to check on the welfare of her students. She was using her smartphone to videotape police encounters. While witnessing an arrest, she recalled shouting something to the effect, “These are students, not criminals. Leave them alone.”

The next thing Orleck knew she was getting knocked to the ground from behind. A cop grabbed her phone.

Videos taken by other people on the Green show police dragging Orleck away from the crowd like a rag doll.

Lebanon attorney Charlie Buttrey, who was representing Orleck pro bono, asked Pastore for the police reports detailing his client’s arrest. A New Hampshire state trooper wrote in his report that Orleck “fell to the ground without being touched.” Another trooper wrote that he watched Orleck “step on her own foot and fall onto her right side.”

It sounds like Pastore didn’t find the state troopers’ accounts credible. Otherwise, why didn’t she charge Orleck?

I also wonder if Dartmouth didn’t weigh in. Orleck’s arrest made The New York Times. Prosecuting a 65-year-old Jewish professor who was standing up for her students could lead to more negative national publicity. With Beilock at the helm, Dartmouth more than ever is about protecting the brand.

From the Dartmouth administration’s perspective, Orleck needs to go away, except she won’t. “It’s not over until the charges against everyone are dropped,” she told me.

Some of the students she’s teaching this summer term are among the 55 still trapped in the criminal justice system. “I see my students every day and the psychological toll it’s taking on them,” she said.

Christian Harris, 32, also came to the defense of students who police were corralling. But for reasons that Pastore hasn’t divulged, his case is headed to Lebanon District Court, along with 54 others.

Harris, who grew up in Hanover, is a paralegal with Vermont Legal Aid, working on the nonprofit’s Housing Discrimination Law Project. He’s planning to start law school next year.

Harris heard about the demonstration only shortly before it began. “I wanted to show my solidarity” with the Dartmouth students, he said. “I didn’t expect the riot police to show up, but I’m glad I went.”

“It wasn’t my first rodeo,” added Harris, who is Black, referring to other protest movements he’s joined, including Black Lives Matter.

Harris linked arms with people who had formed a circle around a tent encampment that protesters were setting up on a sliver of the massive Green.

When dozens of cops from across the state responded with a show of force, Harris said he might have shouted something that police took offense to.

“I got slammed to the ground,” said Harris, who played quarterback at Hanover High School.

Like the other defendants, Harris has pleaded not guilty. “My plan is to see this all the way through,” he said. One reason is to keep the heat on Dartmouth’s administration for “cracking down on a peaceful protest.”

Using her prosecutorial discretion, Pastore has opted to treat the criminal trespass cases as violations — much like alleged traffic offenses, such as texting while driving.

As I’ve written before, Pastore is highly regarded in Upper Valley legal circles. With students arriving soon for the fall term, I don’t doubt that she’s getting pressured by Dartmouth to send a message that pro-Palestinians protests won’t be tolerated on its campus. It wants no more nights like the one that drew hundreds of people to the Green in solidarity.

Still that’s no excuse for keeping the public in the dark.

Jim Kenyon can be reached at jkenyon@vnews.com.