The video depicts a level of cruelty that seems inconceivable. Yet it unfolds before your eyes: A cellphone video, posted for live consumption on Facebook, shows a mentally disabled young man from the Chicago suburbs with his mouth taped shut and his wrists bound as four people punch, cut and mock him.

The story of this incident rapidly went global — yet another act of inhumanity in a city that notoriously ended 2016 with 762 homicides.

Walk through this slowly:

Chicago police say the disabled man met with an acquaintance at a suburban McDonald’s on New Year’s Eve before being held against his will days later on Chicago’s West Side.

The video broadcast live on Facebook shows him tied in a corner as his captors cut his shirt and slice his scalp. Police say he was forced to drink toilet water.

Police charged four suspects with aggravated kidnapping, hate crime, aggravated unlawful restraint and aggravated battery with a deadly weapon.

Equally ghastly is the sound track. A woman belly laughs as one of the offenders slices hair from the young man’s scalp, bloodying him.

“Let me see ... ooh,” she cackles.

The behavior is monstrous.

Police Superintendent Eddie Johnson called the acts on the video “reprehensible” and racist. At one point, the offenders lash out against “white people” and Donald Trump. All the while, the victim sits in a corner, defenseless.

He was able to get away when his captors confronted a downstairs neighbor and the neighbor called police. On Tuesday evening, police found him wandering, disoriented, injured and wearing shorts in the cold weather. They called an ambulance. They learned he had been reported “missing and endangered.”

We leave questions of guilt or innocence to the courts. But any offenders convicted of these crimes likely will face stiff consequences for their actions, which police initially characterized as “stupid” prank-type behavior. Right. Just a bunch of kids goofing around. Police toughened their narrative by the time charges were filed Thursday, as they should have.

For Chicago, then, another grim moment.

It’s become all too routine.

We have the data to prove it.