(CNN) -- When a black man dies at the hands of a white police officer, not often is there video evidence that could end the speculation and show what happened. 

In the case of John Crawford III, there is video evidence -- and Walmart needs to release the tape to the public immediately. 

Crawford was 22 years old when he and his girlfriend went to the Walmart last month in Beavercreek, a suburb of Dayton, Ohio. They planned to pick up the ingredients for s'mores for a family cookout. Crawford had two young children. 

While browsing, he picked up an unpackaged BB gun from one of the store shelves, and continued shopping. A man named Ronald Ritchie saw him and called 911. A black man was "walking around with a gun in the store," and "pointing it at people," Ritchie told them. 

A few minutes later, Crawford was dead -- shot on sight by police. His last words? "It's not real." The gun was a toy, and it was unloaded. 

(Absurdly, if Crawford had been carrying a loaded assault weapon in a threatening manner, it would have been legal under Ohio's open carry laws. This is exactly why gun safety advocates like myself have so long criticized these laws for creating a culture of fear.) 

Was Ritchie more likely to see phantom danger and call the cops because Crawford was a black man? Were those cops more likely to pull the trigger -- by all accounts, without warning Crawford -- because Crawford was black? In other words, is Crawford dead today because he was black in America? 
Who was in walmart?
Crawford was 22 years old when he and his girlfriend went to the Walmart 