“Let the Fire Burn” screens at 7 p.m. Thursday, Nov. 7, at the Madison Museum of Contemporary Art as part of its Spotlight Cinema series. Not rated, 1:35, three and a half stars out of four.

Jason Osder’s documentary “Let the Fire Burn” opens with what looks like some kind of natural disaster, a massive inferno that engulfed a Philadelphia neighborhood in 1985, destroying 61 homes and killing 11 people, five of them children.

But the real horror comes as Osder pieces together the events that led up to the fire, showing us that it was easily preventable, that at best city and police officials acted with gross negligence. At worst, they committed mass murder.

The fire capped a decade-long struggle between the city of Philadelphia and a radical urban movement called MOVE, whose back-to-nature commune initially seems just kind of freaky, with children running naked and only allowed to eat fruits and vegetables. But they got under the burr of 1970s Philadelphia mayor Frank Rizzo, and a decade-long feud began, with the MOVE members becoming increasingly threatening, standing on the rooftops brandishing weapons. “That’s what’s wrong with this country,” Rizzo grouses at a press conference. “We’re backing off too much.”

A 1978 standoff between MOVE members and dozens of police officers resulted in a police officer being killed, and the fuse was lit. Nine MOVE members were sent to jail, but others moved into another row house, building a wooden bunker on the roof and shouting obscenities at neighbors through megaphones. Residents begged the city to do something, and, on May 13, 1985, hundreds of officers surrounded the walled-up compound, determined to put an end to MOVE once and for all.

Osder pieces together what happened next entirely using archival footage — there are no modern-day talking heads and very few title cards. Instead, he relies on local news reports, footage of a city inquiry into the incident, and, most heartbreakingly, the deposition of one 13-year-old boy, Michael Ward, who was one of only two survivors of the fire.

The technique gives “Let the Fire Burn” a gripping you-are-there immediacy, and Osder’s deliberate evenhandedness robs us of the distance to pass judgment on one side or the other. One can’t blame police and city officials (even the chest-thumping Rizzo) for become increasingly frustrated and worried by MOVE’s antics. And one can’t blame MOVE members for becoming increasingly paranoid that the city was going to wipe them out.

In the end, “Let the Fire Burn” is a tragic story of two groups who lost the ability to see each other as human beings, setting both on an inexorable path to conflagration. While the film is a blistering document of its time, it’s also a sobering reminder of how quick we are to demonize those we don’t understand, and how easily this could happen again.