US man charged over wife's Facebook murder

A Florida man who allegedly gunned down his wife and then posted a picture of her dead body on Facebook was charged with murder on Friday.

Derek Medina, 31, was ordered to be held in jail without bail following the macabre slaying of wife Jennifer Alfonso on Thursday.

First degree murder is punishable by death in Florida. Medina must appear before another judge in 21 days time.

Medina appeared in court via closed circuit television from the psychiatric ward of Miami-Dade Country jail where he is being held.

He appeared wearing a black protective vest commonly used for psychiatric patients or detainees who have been placed under suicide watch.

An arrest affidavit revealed Medina confessed to having shot his wife after an argument about her leaving him unfolded at their home on Thursday.

The incident attracted media attention after Medina uploaded a gruesome picture of his slain wife's blood-soaked body on Facebook, under the caption "RIP Jennifer Alfonso."

The photo remained online for several hours before being taken down.

"I'm going to prison or death sentence for killing my wife love you guys miss you guys takecare Facebook people you will see me in the news," Medina wrote on the site.

"My wife was punching me and I am not going to stand anymore with the abuse so I did what I did I hope u understand me."

The affidavit was consistent with the events described by Medina on Facebook, noting that he told police that "he committed a murder by shooting his wife."

Police then visited the couple's home and discovered the victim's body on the kitchen floor. She had suffered multiple gunshot wounds.

According to the affidavit, Medina said the eventual victim "began punching him several times with a closed fist," which led him to arm himself with a gun.

When he confronted her she armed herself with a knife.

The document said Medina had recounted how he had disarmed his wife but she "began punching him again, at which point he discharged his firearm multiple times into the victim."