Omar Thornton, 34, called 911 after shooting 10 co-workers - eight fatally - on Tuesday morning at Hartford Distributors. He introduced himself as "the shooter over in Manchester" and said he was hiding in the building, but would not say where.
"You probably want to know the reason why I shot this place up," he said, his voice steady. "This place is a racist place. They treat me bad over here. They treat all the black employees bad over here, too.
"So I took into my own hands and handled the problem," he said. "I wish I could have got more of the people."
Connecticut State Police released the audio of the 911 call on Thursday, the same day company and union officials rebutted suggestions that the company had ignored Thornton's complaints of racism.
Thornton went on his rampage moments after he was forced to resign when confronted with videotaped evidence that he had been stealing beer and selling it.
His relatives and girlfriend had suggested his anger was fueled by racial bias in the workplace, but the 911 call confirmed Thornton believed he was avenging racist treatment.
Hartford Distributors president Ross Hollander said there was no record to support claims of "racial insensitivity" made through the internal anti-harassment policy, the union grievance process or state or federal agencies.
"Nonetheless, these ugly allegations have been raised and the company will cooperate with any investigation," Hollander said.
The union said 14 of 69 dock workers, or 20 percent, were racial minorities - four black, nine Hispanic, one Asian.
The 911 operator attempted to keep Thornton on the phone and to talk him into surrendering. Thornton said he would not give up his location in the building and knew police were looking for him.
"When they find me, that's when everything will be over," he said, assuring the operator he was not going to kill anyone else.
He then said he saw a SWAT team and hastened to get off the phone.
"Tell my people I love them and I gotta go now," he said.
Police found him dead with a gunshot wound to his head.