After Mario Gonzalez, 26, became unresponsive, officers used chest compression to try to revive him, according to footage of the April 19 incident, which was released late on Tuesday.
Gonzalez died in a hospital that day, according to an initial statement by the city last week.
Protests over police violence and racial inequality have spread across the country in the 11 months since the killing of George Floyd, an African-American man, in Minneapolis by a white officer, Derek Chauvin, who was convicted of murder last week.
In Alameda, a city of nearly 80,000 people adjacent to Oakland, officers were dispatched to a park to check on Gonzalez after residents in two emergency 911 calls reported a man was loitering and appeared to be talking to himself, according to recordings of the calls released by the city.
The officers' body camera footage shows at least two officers approaching Gonzalez and trying to determine his identity. One officer asks where Gonzalez got what appear to be bottles of alcohol in one of two shopping baskets, and says he needs to identify him to make sure there are no outstanding arrest warrants for him.
The officers then try to take Gonzalez into custody and struggle to get both his hands behind his back, the footage shows. They tell the man to stop resisting and eventually wrestle him to the ground, with his body facing downward.
"Mario, please do not resist us," one of the officers says.
Content warning: Police in Alameda, CA kneel on the back of Mario Gonzalez for 5 minutes as he cries in agony.One officer says “think we can turn him on his side?” The other says no. Twenty seconds later he’s dead. pic.twitter.com/6J9YpM1xIe
— Sawyer Hackett (@SawyerHackett) April 28, 2021
The officers then struggle for a little over five minutes to keep Gonzalez pinned and to get both his hands behind his back so they can handcuff him. One of the officers has his knee on the man's shoulder to hold him down.
Gonzalez can be heard uttering "Ahhh, ahhhh" during the scuffle.
"I think you just had too much to drink today, that's all," one of the officers says.
They then check for a pulse. When Gonzalez does not respond, they turn him over and begin chest compressions before paramedics arrive. An initial statement from the city says a "physical altercation ensued" after officers attempted to detain Gonzalez, who they said had suffered from "a medical emergency."