The Massachusetts Supreme Justice Court holds oral arguments in appellate cases during the first week of each month from September to May. Morning Edition host Joe Mathieu spoke with Northeastern University law professor and WGBH News legal analyst Daniel Medwed about some of those cases. The transcript below has been edited for clarity.

Joe Mathieu: So what are the big cases we should be focused on this week?

Daniel Medwed: Yesterday, the SJC heard oral arguments in a very high-profile case involving an African-American man, Michael Gannon, who applied for a job with the Boston Police Department. But he was turned down because a forensic drug test detected the presence of cocaine in his hair. Now, these tests are notoriously unreliable. There's a high risk of external contamination and false positives, especially for African-Americans. Because of the texture of the hair of many African-Americans, drug particulates that are floating around in the air can become lodged in the follicles [and] create a false positive. But this appeal is not so much about the hair test — the reliability or unreliability of them — as it is about Michael Gannon. What should happen to him procedurally, in terms of his claim for relief?

Read more: State's Highest Court To Weigh In On Controversial Hair Drug Test Used By The Boston Police

Mathieu: Which was what?

Medwed: Well, essentially, he wanted an opportunity to work for the Boston Police Department. So he filed a grievance with the BPD that went up to the state civil service commission, which said yes, the BPD discriminated against him in this faulty hiring decision. But then a trial court intervened [and] overturned the commission's decision on procedural grounds. And now we find ourselves in the SJC, waiting.

Mathieu: And it will be sometime time, I suspect. So Daniel, there are a couple other cases in this week’s lineup. What else are you focused on the docket here? Any significant criminal cases?

Medwed: Well, the one I have my eye on is a case called “Commonwealth vs. Grassi.” It's a murder conviction related to a stabbing at a high school graduation party in East Wareham several years ago. The defendant, who was 18 at the time, was convicted at trial. But on appeal, he's taking issue with the grand jury process. That's the process through which prosecutors present evidence to charge someone with a crime. He claims that the grand jury in his case should have been instructed about mitigating evidence — evidence that points to his innocence — like self-defense. Now, I find this fascinating because on the one hand, the grand jury is typically the prosecutor’s turf. There's that old adage that a grand jury would indict a ham sandwich. Well, the prosecutor puts that ham sandwich on the platter, they present the evidence in the way that they want. They can even introduce evidence that's inadmissible at trial, like hearsay. They don't have to introduce evidence that exculpates the accused, typically. But on the other hand, there's an important 2012 case called Walczak, in which the SJC held that for juvenile defendants — folks under the age of 18 — they deserve to have instructions at their grand juries about mitigating evidence. So here the defendant wants to extend that Walczak principal to all criminal cases.

Mathieu: So, put your crystal ball out here. How do you think this will turn out?

Medwed: Oh gosh, I wish I could look into the crystal ball. But I do think that the SJC should extend the principle and I think that they might. For one thing, we live in a world where almost every case — over 90 percent of cases — are resolved through plea bargains, which means that the grand jury process is critically important. There are very few trials, so why not make that process less of the prosecutor's turf. Make it a little bit more balanced, a little bit more searching and robust. Second, back in that Walczak opinion in 2012, three of the seven SJC justices — just one shy of a majority — wanted to extend the principle that grand juries should hear about mitigating evidence to all criminal cases. One of those three justices is the current Chief Justice Ralph Gantz, which makes me think there might still be some strong lingering sentiment in favor of broadening this principle. I know it seems a little bit technical, but it is pretty fascinating.