Presented by stock photography.

(Shutterstock/Brad Camembert)

The FBI on Tuesday posted to their blog the story of Christopher Patrick Gunn, sentenced to 35 years in prison for pretending to be Justin Bieber and asking people for nude photos online.

The post also gives a list of tips on how best to avoid being "sextorted" by strangers online. The FBI also pointed to the story of Karen "Gary" Kazaryan, alleged to have stolen nude photos from more than 350 women.

From the blog post:

"The basic framework of the extortionist's scheme was as cold as it was calculated: contact a young girl on a social networking site using a fake identity, gain her trust, extract some highly personal information, and then threaten to expose her intimate exchanges if she doesn't assent to escalating demands for sexually explicit pictures or videos."