The verdict follows a weeklong trial in which Medina's attorneys tried to present the killing as an act of self-defense. Indeed, in the infamous Facebook post, Medina wrote that his wife was punching him, and he implied she had a history of abusing him.
Prosecutors, however, presented evidence that it was Medina who had a history of abusing his wife. Alfonso's friends testified that she had told them that Medina had threatened to kill her if she ever left him. Medina's attorneys claimed Alfonso had pulled a kitchen knife on him, but a medical examiner testified that the angle of the eight gunshot wounds indicated that Alfonso must have been cowering below Medina at the time of the murder.
The incident happened in August 2013 in the couple's South Miami townhouse.
"He planned to execute Jen, and he executed his plan," prosecutor Leah Klein said in her closing argument. "He was angry, and he wanted her dead."
Prosecutors also pointed to Medina's winning record as an amateur boxer as evidence that he was more than capable of defending himself.
Medina also had a history of writing several oddly titled self-help-themed e-books, including the tomes How I Saved Someone's Life and Marriage and Family Problems Thru Communication and World Just Ask Yourself Why We Are Living a Life Full of Lies and How I an Emotional Writer Made All of My Professional Dreams Come True Blocking Society's Teachings.
The defense tried to present evidence that Alfonso, a waitress at a local Denny's, dabbled in some drugs and worshipped Satan. The judge did not allow the evidence to be presented.
Medina was also found guilty of the illegal discharge of a firearm inside a building and child neglect because Alfonso's 10-year-old daughter was in the home at the time. The girl did not witness the shooting.
"No family should ever have to see their daughter killed and then exhibited worldwide on the internet like some macabre trophy to a husband’s anger, as was Jennifer Alfonso," State Attorney Katherine Fernandez Rundle said in a statement. "Far, far too often, this kind of domestic violence leads to injury and death. That’s why we all must end all forms of domestic violence. The jury carefully viewed all the evidence and came to the correct conclusion that Derek Medina coldly murdered his wife to heal his own injured ego."
Rundle indicated that prosecutors will seek life imprisonment when Medina is sentenced.