Demetrio Jackson was desperate for medical help when the paramedics arrived.

The 43-year-old was surrounded by police who arrested him after responding to a trespassing call in a Wisconsin parking lot. Officers had shocked him with a Taser and pinned him as he pleaded that he couldn’t breathe. Now he sat on the ground with hands cuffed behind his back and took in oxygen through a mask.

Then, officers moved Jackson to his side so a medic could inject him with a potent knockout drug.

“It’s just going to calm you down,” an officer assured Jackson. Within minutes, Jackson’s heart stopped. He never regained consciousness and died two weeks later.