Derek Medina, right, posted a picture of his slain wife's body to Facebook and then turned himself in for her murder.

Story highlights

Crimes, both minor and major, get confessed on social media surprisingly often

A Miami man allegedly killed his wife and posted a photo of her body on Facebook

Experts say some criminals have always boasted of their crimes

Social sites, they say, make it easier to forget consequences

CNN  — 

Committing such heinous crimes as sex abuse and murder are unthinkable enough to most of us. But it’s almost equally mind-boggling that the perpetrators would then confess, or even brag about, such acts on the Internet.

Even so, in cases as mundane as vandalism or as horrifying as gang rape, accused criminals are exemplifying a growing truth of the social-media age: To some, nothing is too sacred, private or damning to share online.

“Social media exposes the crimes, along with the poster’s need to feel important or powerful,” said Pamela Rutledge, director of the Media Psychology Research Center at the Massachusetts School of Professional Psychology. “However, in most cases, it appears that the need for bravado is much greater than any concerns about getting caught.”

The latest high-profile instance happened Thursday, when a Florida man allegedly killed his wife and posted a photograph of her body, along with a confession, on his Facebook page.

“Im going to prison or death sentence for killing my wife,” wrote Derek Medina, 31, of South Miami. “(L)ove you guys miss you guys takecare Facebook people you will see me in the news.”

The gruesome image was shared thousands of times before Facebook was alerted and deleted it several hours later.

It shocked his own Friends list. Among the responses: “WHAT??????” “What happened???? derek.”

But social-media posts about crimes are surprisingly common. Just a few of the most widely publicized in recent times:

– An investigation into the rape of an unconscious 16-year-old girl by high school football players in Steubenville, Ohio, began after some of the accused posted pictures and video of the girl on Facebook, Twitter and Instagram.

– The alleged 2011 rape of Rehtaeh Parsons, then 15, in Novia Scotia by four teens was discovered after the teens reportedly shared a photo of her online and via text messages. Two of them, now adults, were charged with child pornography this week. Parsons, at age 17, hanged herself and, in April, was taken off life support.

– In 2011, a Pennsylvania teen pleaded guilty to raping an intoxicated 15-year-old girl, then turned to Facebook, looking for a hit man to kill her. ” “I got 500 on a girls head who wants that bread?” he wrote. “Hit me up anyway possible.” The man who responded was, in fact, an undercover detective.

– A Hawaii man was charged after posting a video titled “Let’s Go Driving & Drinking!” in which he appears to open and drink a beer while driving and talking to a camera for more than five minutes.

READ: When oversharing online can get you arrested

Michele Nealon-Woods, national president of the