(CNN) -- A Miami man who shot and killed his wife during a fight at their home in August and allegedly uploaded a picture of her corpse to his Facebook page told police he was defending himself, officials said.
"I'm not a killer," Derek Medina said in an August video released Friday by prosecutors. "I do not feel that I'm guilty and I feel like this was self-defense."
Medina, who has pleaded not guilty to second-degree murder, said he and his wife, Jennifer Alonso, were having an argument in the bedroom when "she started throwing stuff, objects, towards me," such as towels, mascara, creams, boxes and shoes.
"Anything in the room she could throw at me," said Medina, who told police he had been an amateur boxer with a 25-0 record. " ....I got hit in the face a few times."
Medina gave these additional details, as outlined in a Miami-Dade Police Department transcript accompanying the video:
At one point, he pulled a gun on his wife and told her to stop. After further discussion, he put the gun away and Alonso told him she was leaving him. They talked again downstairs, where she unloaded a volley of punches on him. He fetched the gun again. She pulled a knife. He wrestled it out of her hands and put it in a drawer.
"She just started throwing punches like crazy. She was like really attacking me," he told police. "Like I was getting out of the way and got hit in the arm and she was like going for my temple."
Medina told police that Alonso threatend to kill him with a knife, but he disarmed her. He told police Alonso also said she would have someone kill him. Medina said as the fight continued, he shot his wife "six to eight times."
Medina told police he suffered injuries from his wife's pushing and punching.
According to authorities, Medina wrote on Facebook, "Im going to prison or death sentence for killing my wife love you guys miss you guys take care Facebook people you will see me in the news."
The gruesome image of Alonso stayed online and was passed along for at least five hours. Facebook was notified of the content and employees removed the picture and disabled the pages of Medina and his slain wife.
An autopsy report released on Thursday said Alonso suffered gunshot wounds to her left forearm. Some of the bullets traveled at a downward angle, with one bullet entering her right chin, lodging in her back at the right side of her ribs.
Gunpowder residue was found on her left hand and forearm, and the right side of her neck and chin. Seven bullets and two bullet fragments were recovered.
Journalist Mayra Cuevas contributed to this report.