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Derek Medina Update: Surveillance video captures moments before Fla. man allegedly kills wife, posts photo on Facebook

Derek Medina
CBS Miami

(CBS/AP) MIAMI - A home surveillance video shows Derek Medina, a South Florida man accused of killing his wife and then posting a bloody picture of her body on Facebook, walk away from a confrontation with his wife and then return a few moments later to fire a gun.

PICTURES: Fla. man posts pic of dead wife, confession on Facebook

The weapon can't be seen in the video released Tuesday by the Miami-Dade State Attorney's Office to The Miami Herald, but the camera did pick up the swirl of gunpowder in the air from when authorities say Medina, 31, fatally shot Jennifer Alfonso, 26, at their South Miami home on Aug. 8.

The footage also shows Medina calmly retrieving a jacket and his phone, apparently stopping to take a photo of Alfonso's body and then walking out of the townhome. He turned himself in a short time later at a South Miami police station.

Medina is charged with second-degree murder, but prosecutors will likely seek a first-degree murder indictment in the coming weeks.

Medina has claimed that his wife was the aggressor in the confrontation and that he was acting in self-defense. He has pleaded not guilty to the second-degree murder charge.

Besides the surveillance footage, prosecutors on Tuesday also released Alfonso's diary, where she wrote about her relationship problems with Medina, claiming in one entry that she wanted to "rip his eyes right out" after he ogled other women.

"We have the strangest relationship, to me anyway," she wrote in a Dec. 27 entry. "We get angry at each other for the stupidest things."

CBS Miami reports Alfonso's diary was entitled, "The Mind of an Insane Women." [sic]

In the diary Alfonso also writes about ghosts in the house and expresses her unhappiness in her relationship, according to the station.

In one entry she reportedly writes that she "can't sleep thinking about my unhappy husband and zombies."

Medina made international news last month when he posted the photo of Alfonso's bloody body, slumped on the kitchen floor on Facebook. Alfonso's 10-year-old daughter from a previous relationship was upstairs at the time and was not harmed.

When posting the photo to the social media site, investigators say Medina also posted a confession.

"I'm going to prison or death sentence for killing my wife. Love you guys. Miss you guys. Take care. Facebook people you'll see me in the news," he wrote on his Facebook page.

In another entry, Mediana wrote, "My wife was punching me and I'm not going to stand anymore with the abuse so I did what I did. Hope u understand me."

Facebook later removed Medina's and Alfonso's Facebook pages at the request of law enforcement.

Complete coverage of Derek Medina on Crimesider