Social media is changing almost everything about our lives, including criminal activity, which is finding a new home online -- and police are using it to their advantage.

Take, for example, a viral video that's almost too hard to watch. A disabled man attacked in Fleming Island while trying to play basketball.

"I was just appalled because big mike, he's just a sweetheart. no one messes with him," said 17-year-old Kayla Shipp via Skype.

The former Clay County resident is the person who found the video on Facebook and called police.

"All he wanted was his basketball so he could go home," she said. "So it definitely pulled my heart strings."

The tip was enough for the Clay County Sheriff's Office to investigate and make an arrest.

"We were able to, through social media, we were actually able to identify the suspect in this case," said Det. Ryan Ellis.

Now, a juvenile has a felony aggravated battery conviction on his record.

"Social media posts can really change things," said Michael Knox. Knox is a former detective who now runs a private consulting firm in Jacksonville.

He said there's been a substantial shift in how social media plays a role in criminal justice.

"For many, many years, the worst thing offenders do to themselves is open their mouth," Knox said.

Now, Knox said offenders are getting themselves in trouble by posting to websites like YouTube, Facebook and Instagram.

"Everybody saw when I ****** choked him, but nobody saw when I ****** smoked him," said a music video on YouTube that police say helped them solve a double murder.

"I hit and killed Vincent Canzoni," said a man who made national headlineswhen he confessed on YouTube he killed someone while driving drunk.

And then, who could forget this case in Florida: A man confesses to his own wife's murder by posting a picture of her body on Facebook.

Then here at home, a picture from Jallil Graves' Facebook page. He's the suspected triggerman in a double homicide at a Jacksonville restaurant.

And last month, an ambulance "selfie." A Jacksonville student shared a picture on Instagram after being stabbed at school.

It was enough to leave one mom who we can't identify in disbelief. "Especially with high school kids and social media … " she said.

Knox said social media can be good evidence for authorities to use, but he said it can also work against them.

"One of the danger areas is a person testifies to one thing and it's found they've posted something different on social media," Knox said.

Take what happened at the George Zimmerman murder trial. The state used a single tweet to try and discredit a defense witness.

"Social media is one of those things that could really come back to haunt both sides, defense and prosecution, depending on what's posted out there," Knox said.

So to protect yourself, here's something to consider about using social media.

"We can go on there and simply browse the internet and we can see things that maybe you thought were private, or maybe your settings really aren't set to private," Ellis said.

"If you're involved in a crime and you go posting about it, you talk about it, you do whatever, all you're doing is potentially putting more nails in your own coffin," Knox said.

They're reminders Shipp believes more people should take to heart.

"Yeah, okay, we can do this and put it on Facebook. There is consequences and sometimes you do get in trouble," Shipp said.

Social media is also forcing law enforcement to change their habits. Multiple agencies on the First Coast tell us they are spending more time monitoring activity online, just like you.