By David Ovalle

A Miami felon nicknamed "Crazy Goat" got cuffed on a weapons rap after posting photos of himself loading guns.

Months later, online snapshots helped police pin charges against three teenagers on allegations of drug-fueled group sex with underage girls. Then there was a petite teen named Karla Sanchez who saw a naked overweight woman in the shower of a North Miami gym. She whipped out her smartphone, snapped a photo and immediately posted it. Her not-so-smart caption: "The things I see at LA Fitness. WTH!"

Within weeks, cops jailed Sanchez, 18, on a misdemeanor voyeurism charge. Each of these recent cases stemmed from photos or video posted on Instagram, the fast-growing social media site that has increasingly become a treasure trove of evidence for police and prosecutors.

Several weeks ago, Miami-Dade detectives sent search warrants to Instagram's corporate office, hoping to obtain posts to seal convictions for two defendants awaiting trial, one of them for murder.

"We encourage the criminals to post their photos and videos online," said Miami-Dade State Attorney Katherine Fernandez Rundle. "After all these years, they're still kind enough to do it."

Spilling the beans on social media has become so common that defense attorney David Seltzer, a former Miami-Dade cybercrimes prosecutor, now makes it a point to caution his clients.

"I think technology has made people relaxed and made people let their guard down," Seltzer said. "First thing I tell clients is, 'Turn off your social media. Why make the job of the police easier?' "

There have been a number of notable social-media crime cases, topped by Derick Medina of South Miami. In 2013, he shot his wife, and then uploaded a photo of her dead body and a confession to his Facebook page.

Medina, who is awaiting trial, claims self-defense.

The yearning to show off, prosecutors say, snagged Bryan Yanes and two other West Kendall teenagers. They're accused of plying girls _ ages 12, 13 and 14 _ with drugs and booze at a pool party before having group sex.

Miami-Dade detectives learned that Yanes, 18, had posted salacious photos of the tryst to the Instagram account known as "loverboybryan." Though Yanes' Instagram account was set to "private," detectives got the photos anyway, with a search warrant sent to the company's California office. The three are awaiting trial for lewd and lascivious battery on children.

Instagram regularly monitors posts and complaints about unsavory photos or video clips. The company also maintains an "Instagram Law Enforcement Response Team" that fields subpoenas, court orders or search warrants signed by a judge.

Prosecutors prefer search warrants _ without one, Instagram and other social media companies notify users if law enforcement requests information on accounts.

"It's important because if a suspect is tipped off, they can start destroying evidence," said Miami-Dade Assistant State Attorney Tom Haggerty, who heads the office's cybercrimes unit.

An Instagram spokeswoman declined to say how often the company cooperates with law enforcement.

In an era of increased wariness over government digital spying, "it's a positive development that the police are obtaining warrants to obtain access to these accounts," Shear said. "This type of evidence is very strong, and it's only going to increase with use in legal cases."

The visual evidence doesn't always lead directly to arrests but bolsters the strength of existing cases.

Miami's Gaurionex Pena, 37, was arrested in September for an alleged tryst with an underage girl.

Two months later, detectives asked Instagram for Pena's account. He allegedly wrote "I love you" on one of her photos, one of several comments "and numerous emojis" he posted, according to the warrant.

In another case, Kimberly Matthews was arrested in April for shooting to death a man during a brawl outside a strip club in South Miami-Dade. She claimed self-defense.

In November, homicide detectives asked Instagram for photos that showed Matthews, 31, wielding the pistol used in the killing _ and to see whether any comments made on the images were incriminating. She is awaiting trial.

Instagram has also proven to be a useful tool for building intelligence on suspected criminals.

Investigators suspected that Miami's Bernardo Olvera, 28, was dealing cocaine. Their opportunity to enter his house came because of photos and video clips publicly posted by Olvera and his girlfriend under the nicknames chivoloco, Spanish for "crazy goat," and "allGucciBitxch."

They depicted Olvera, a convicted felon who can't legally have guns, loading ammunition into weapons. That led detectives to get surveillance video of him at a shooting range.

Armed with a search warrant, cops raided his West Miami-Dade house. They found 267 grams of marijuana and 53 grams of cocaine, according to an arrest report. He is awaiting trial on cocaine trafficking and weapons charges.

At least one other Miami man is doing serious prison time, thanks to Instagram.

In November 2013, serial shoplifter Leroy Minnis stole $2,238 worth of merchandise from the Hollister store at the Sunset Place mall in South Miami.

To sell the hot shirts, Minnis posted photos of them on his Instagram account, "WhoisPuti." Another photo, with two busty woman on each arm, also showed him wearing a distinct black T-shirt with gold lettering _ the same one seen on store surveillance video.

He's now serving a 32-month prison sentence.

(c)2015 Miami Herald