A few weeks ago, about thirty people assembled under cloudy skies on a bluff overlooking the St. Joseph River, in downtown St. Joseph, Michigan. Eric McGinnis, a Black teen-ager from Benton Harbor, the next town over, mysteriously drowned in the river thirty years earlier, on May 17, 1991, and the people had gathered to honor his memory. At one point, the names of others who had died in unresolved circumstances in the area—all of them Black individuals, many the victims of street violence, and some of whom were also found in the river—were read aloud; one of the rally’s organizers rang a bell for each name. Afterward, Pastor Duane Seats, who is a city commissioner in Benton Harbor, spoke to the crowd. Benton Harbor and St. Joseph are both small towns, and so it was unsurprising that Seats had attended junior high school with McGinnis. “That was a cold day when they told us Eric had died,” he said. “They’ve been telling me since the seventies, if you go over there”—to St. Joseph—“you might not come back.”

McGinnis’s death and these two towns were the subject of my book “The Other Side of the River: A Story of Two Towns, a Death, and America’s Dilemma,” published in 1998. The night that McGinnis disappeared, at the age of sixteen, he had been visiting a teen nightclub in St. Joseph, a town of about eight thousand that sits along the coast of Lake Michigan. St. Joseph has the feel of a resort town: it is predominantly white and prosperous, and boasts one of the most-visited shorelines in the area, Silver Beach. On the other side of the river sits Benton Harbor, with nearly ten thousand residents. It is predominantly Black and economically distressed. The two towns are, without irony, referred to as “the Twin Cities.” I was drawn there many years ago not because they were an anomaly, but rather because they seemed emblematic of how most of us live, separate and deeply unequal.

An hour or so before the vigil, a local TV station had reported that the St. Joseph police had reopened the case into McGinnis’s death. Someone had come forward claiming to have witnessed his last moments. My reporting for the book revealed some details about that night. McGinnis was dating a white girl with whom he had danced at the club. It was a slow night, and McGinnis wandered outside, ultimately entering an unlocked car. He grabbed forty-four dollars from the glove compartment. The car’s owner, a middle-aged white man, came upon him and briefly chased him down State Street, past an off-duty detective with the sheriff’s department who was entering a restaurant. (The detective called the police but didn’t join in the pursuit.) McGinnis soon outran the man, but, five days later, men from the Coast Guard Station St. Joseph discovered McGinnis’s bloated body floating in the river. His death was officially ruled an accidental drowning.

For a number of years, I was obsessed with McGinnis’s death. I read and reread police documents, and interviewed his friends and his family. (Both his parents have since passed away.) I spent hours with the chief detective on the case. I spoke with teens from St. Joseph. I tracked down people who claimed to have seen McGinnis that night. I reviewed the autopsy reports with a renowned forensic pathologist. I even canoed the river to measure its currents. Virtually everyone I spoke to in St. Joseph, the white town, was convinced that McGinnis, knowing that the police might be looking for him, had tried to swim the river to get home or had accidentally fallen in while trying to cross a railroad bridge. Everyone I spoke with in Benton Harbor was convinced that McGinnis had died as a result of foul play, most likely because he had been dating a white girl. It was like a Rashomon of race, where people came to this singular moment with a sense of certainty that had more to do with their personal experiences—with which side of the river they came from—than the facts of the case.

The new development broke a few weeks ago. A man from St. Joseph, who was a contemporary of McGinnis’s, came forward to a local TV anchor, Brian Conybeare, claiming to have witnessed McGinnis’s being chased by a small group of white teens and young men. The name of this witness sounded familiar. When I went back through old e-mails, I discovered that, in 2014, he had reached out to me with the subject line: “Please Help Me!” He wrote, in part, “It seems like it just happened yesterday. It hurts the most when I think of how Eric McGinnis gestured to my friend & I for help as he was being chased. . . . I am tortured on a constant basis by my conscience.” He asked if I could help him find an attorney. I wrote to him to say that, if he thought he could identify the people who had chased Eric, then maybe I could help. I never heard back. But, after the case was reopened, we spoke briefly on the phone. He told me that he has asked for immunity before he will agree to talk to the police. A task force involving detectives from three area departments has been created, and they have begun interviewing or re-interviewing people who may have been present the night that McGinnis disappeared.

Since I was there in the nineteen-nineties, parts of Benton Harbor have undergone a revitalization of sorts. Whirlpool, which maintains its headquarters on the outskirts of town, has established an office complex on West Main Street, and, in 2010, helped build a lakefront golf course that has hosted the Senior P.G.A. Championship. And, adjacent to the course, along the river, is a development of newly constructed homes. In a corner of downtown, an easy walk to the golf course, a handful of old factories and warehouses have been converted into condos, and a vibrant arts community has put in stakes. Richard Hunt, the renowned Chicago sculptor, opened a studio there.

At the Mason Jar, a coffee shop in the arts district, I met Trenton Bowens, a local activist and school-board member, who founded a group called Neighbors Organizing Against Racism. The group, which involves about a hundred people from both sides of the river, gathers to talk about issues of race in the two towns. Bowens, who is thirty-two, wore a Kangol cap and a zippered sweatshirt. He immediately mentioned the development downtown and the golf course. “The question we have to ask, Is it gentrification or revitalization?” he said. “Look around this restaurant. There’s only one other table of Blacks here.” The median household income in Benton Harbor is $21,916. In St. Joseph, it’s $62,374. Bowens offered to drive me around the city’s neighborhoods. We drove down Pavone Street, which was lined by wood-framed homes, many in disrepair, many boarded up. It was here, Bowens reminded me, where, in 2003, a motorcyclist, who was Black, crashed into a building while being chased by police. After his death, residents rioted. Thirteen buildings were set on fire. As the New York Times reported at the time, people were upset by a number of unexplained Black deaths, including that of McGinnis. “It was years of frustration,” Bowens said.

As I write in my book, these two Americas, side-by-side, aren’t an accident of geography. Rather, they’re an exclamation point on the modern-day history of race in the North. In the nineteen-forties and fifties, Black men were recruited from the South, mostly from Arkansas, to work in the local foundries and auto-parts plants. Global competition killed off many of these factories, and then whites, uneasy with their new neighbors, fled to the other side of the river. The newspaper, the Y.M.C.A., the hospital, even the local F.B.I. office soon followed. What felt like the final blow came when half the members of the First Congregational Church of Christ voted to take their prayers and their God to St. Joseph. It’s been the plight of Benton Harbor that most anything of value either leaves or gets snatched up by others.

Two years ago, the state of Michigan announced that it planned to close Benton Harbor’s lone high school, because the school district was eighteen million dollars in debt and its schools were underperforming. Students would be bused to surrounding schools, including St. Joseph High School. The community erupted in protest. “That’s one of the only things Benton Harbor has,” Bowens told me. “We no longer have a hospital, so no one can say they were born in Benton Harbor. You take away the high school, no one can say they graduated from here.” Some believed that the state wanted to take the high school so that it could sell the acreage to private developers; the campus sits atop a hill with a panoramic view of the river. The school board, in an act of defiance, unanimously voted to tell the state to keep its hands off. “No question,” Bowens said, “it was a Black-versus-white thing.”