
Volume 20 · Chapter 8
The Facebook Killer
Derek Medina
Victim: Jennifer Alfonso
Case at a glance
- When
- August 2013
- Where
- South Miami, Florida
- Perpetrator
- Derek Vernon Medina
- Victim
- Jennifer Alfonso
- Outcome
- Convicted of second-degree murder in November 2015 and sentenced in February 2016 to life with parole eligibility after 25 years; upheld on appeal in 2018
The case
Derek Medina and Jennifer Alfonso married in 2012 and lived in a townhouse in South Miami, Florida. Medina had self-published short books on marriage, faith and self-improvement. The marriage was brief and volatile, and friends later told a jury that Alfonso had said he threatened to kill her if she left him.
On the morning of August 8, 2013, the two argued in the bedroom and the fight carried into the kitchen. Medina, who was thirty-one, shot Alfonso eight times. He then photographed her body, uploaded the picture to Facebook with a post saying he expected to go to prison, drove to his parents’ house to tell his father, and turned himself in. He never called 911. Alfonso’s ten-year-old daughter was in the house and was found unharmed; she had not seen the shooting. Medina claimed self-defense, but the knife he said she used was found clean in a drawer, and the medical examiner testified that all eight shots angled downward and that Alfonso was low to the floor when she was hit.
A Miami-Dade jury rejected the self-defense account in November 2015, convicting Medina of second-degree murder, unlawful discharge of a firearm in a building and child neglect. In February 2016 he was sentenced to life with parole eligibility after twenty-five years. Florida’s Third District Court of Appeal upheld the conviction and sentence in November 2018.
Read the full story
This case is told in full in True Crime Case Histories, Volume 20 by Jason Neal.
Get Volume 20 on AmazonCase photographs
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Where it happened
Why this case
“Social media changed how a case like this surfaces, not what it is. Jennifer Alfonso’s death was a domestic homicide that a man chose to publish because he wanted an audience for his version of it. I spent most of the chapter on her, and on the child in the next room, rather than on the post everybody remembers.”
— Jason Neal, author of True Crime Case Histories










