MIAMI — Derek Medina's life was open to the world.
On YouTube, the 31-year-old South Miami man posted scores of videos of himself enjoying sports.
He wrote six online books with long-winded titles about spirituality, saving the world and hunting ghosts. Medina snapped photos of his arm tattoos, meals, boating trips and drinks poolside with his wife.
But on Thursday, Medina shocked many by making one last announcement on Facebook — he had killed his wife, Jennifer Alfonso, 26, before posting a photo of her twisted, bloodied body lying on a linoleum floor.
"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," Medina wrote in a Facebook post that remained public for hours Thursday evening before the site removed his profile page at the request of police.
Even in a world accustomed to intimate details of people's lives plastered on social media, Medina's posts — which went viral — were stunning.
Medina walked into the South Miami police station about noon Thursday, then spent the evening speaking with homicide detectives.
Miami-Dade police, which handles homicide investigations for South Miami, had yet to announce whether Medina would face charges.
Investigators obtained a search warrant and began documenting the crime scene inside the couple's townhouse at 5555 SW 67th Ave.
Alfonso's 10-year-old daughter from a previous relationship was upstairs at the time of the killing and was physically unharmed. Officers quickly escorted her out of the home after finding Alfonso's body.
Medina is likely to claim self-defense.
His father, Derrick Medina Sr., told reporters that his son killed Alfonso only after she brandished a knife.
In the younger Medina's Facebook post, he did not mention a knife but 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."
Alfonso's former boss at a West Miami-Dade Denny's told the Miami Herald that the husband was extremely jealous and had hit Alfonso in the past.
"She would be bruised up," said Amada Cooper, who described Medina as a controlling husband who tried to force Alfonso to quit her job as a server because he didn't want her working nights.
Medina and Alfonso initially married in early 2010 after dating just a few months. They divorced in early 2012, then remarried a few months later, records show.
Cooper said the two fought often because Medina could not hold a job for more than a few months.
On his Facebook page, Medina claimed to be a supervisor at a property management company and to have appeared in the Miami-based crime drama Burn Notice, though his name doesn't appear in online credits for the show.
The Facebook page said Medina had 164 friends. His post on Alfonso's killing was shared by more than 100 people on the networking site before Facebook shut down the account.