Not everyone looking at your profile on Facebook and trying to connect with you is looking to be your friend.

In May, in what was meant to be kidnapping scheme turned fake rescue, a 15-year-old girl was murdered by a man pretending to be a teenager on Facebook. Kyle Dube of Orono, Maine, used his assumed identity to trick his victim, Nichole Cable, to meet him down the road from where she lived in order to procure marijuana, according to the affidavit released after Dube’s indictment. There, in an attempt to abduct Cable, Dube in fact killed her.

NEWS: Cyber Criminals Target Social Networks

Stories of criminals exploiting easy access and information to individuals through social media networks frequently focus on nonviolent crimes like identity theft, burglary or fraud. But violent criminals can take advantage of the same channels to target their victims as well. Cable’s case is tragic, but it’s not unique.

In 2010, an 18-year-old Australian animal lover, believed she was pursuing a job offer with an animal welfare group when she met 20-year-old Christopher James Dannevig. They met at a creek south of Sydney, which she thought was for a camping trip to scout for injured animals. There, Nona']Dannevig murdered the young woman.

Teenagers and younger adolescents are frequently the targets of violent criminals on social media. There have of course been cases of older users who have become victims.

Take the case of 28-year-old Josh L. Tyree in 2011, who had arranged a date with 24-year-old Tara Bell of Lima, Ohio. Instead of a romantic evening out on the town, Tyree was instead met by two others in addition to Bell: Latasha Ward, who served as a lookout, and Bo Guedea, who robbed Tyree at gunpoint and shot him in the leg.

PHOTOS: Long-Lost and Found: Missing People Who Were Found

In the case of 23-year-old mother-of-two Leah Gibbs of South Wales, U.K, she was part-victim, part-unwilling accomplice of a Facebook meetup with a stranger gone awry.

Upon rendezvousing with 21-year-old Adam Minton, he asked her to drive to a nearby bookie. He went inside by himself, and then minutes later came running out with a knife in one hand and a bag of cash in the other, shouting at Gibbs to drive away. Both were later arrested at Minton’s house, though the criminal told police he acted alone.

Some criminals give their victims one bad day, but in the case of 23-year-old Jason Smith in 2009, he terrorized Alexandra Scarlett through her Facebook account for nearly two years. Because she refused to go out with him, Smith assailed her with messages threatening her family and her life, sending up to 30 such threats in a single day. Even though Scarlett would shut down her accounts and open new ones, Smith would still track her down. Smith was eventually arrested and charged with harassment.

Given the potential dangers posed by violent criminals, be they armed robber, sexual predators, cyber stalkers or murderers, the Federal Bureau of Investigation (FBI) has put together guidelines of what parents of young children and teenagers can do to prevent an online encounter from turning into an offline tragedy.

Tips include teaching kids about their privacy setting to avoid unnecessarily disseminating personally identifiable information and reminding them to only interact with people they know in person.

Photo: Kyle Dube (right) faces a sentence of 25 years to life in prison for the murder of Nichole Cable (left). Credit: Nichole Cable, Facebook; Kyle Dube, Handout