Updated

A Fox 10 Exclusive

Jodi Arias is at the center of one of the highest profile murder trials the valley has ever seen. And now she's tweeting from behind bars.

FOX 10 News has learned that Jodi Arias is operating her own Twitter page from jail, communicating with hundreds of followers — mocking the prosecutor and even taking shots at cable host Nancy Grace.

The last tweet went out Tuesday night to her more than 500 followers.

Sounds like any normal person tweeting about their lives. But the person behind these tweets is the most famous defendant in the world.

But how can Jodi Arias use Twitter from jail? She doesn't have a computer. She does it through this woman – Donavan Bering – a close friend Jodi talks to almost every night on the phone.

Donavan Bering was sitting with Jodi's mother in court today.

"She'll call and say 'I have a quote.' We'll talk about it. Sometimes she says 'let's tweet.' And then she'll say 'no let's not do it.'"

Through Donavan, Jodi has been using Twitter to go after prosecutor Juan Martinez.

Tweeting, "Hmm… Anger Management problems anyone?" – "He who tries to establish his point by much yelling shows that his reasoning is weak." And – "Those afflicted with Little Man's Syndrome taint society's perception of genuinely good men who happen to be vertically challenged."

She went after HLN's famous court watcher Nancy Grace. When Grace tweeted a picture of her that appeared to show her making an obscene gesture with her hand in court, she tweeted, "Actually Nancy, that finger was for you. Have a nice day." And "HLN is an acronym for Haters Love Negativity."

"I think it's a way of her getting out her frustration, because she doesn't have a chance to say much," explains Donavan.

But she also uses Twitter to further what appears to be a healthy business selling her art from behind bars.

Jodi tweeted, "eBay has banned all listings of my artwork. The silver lining in making my art more difficult to obtain is that it keeps increasing in value."

The Maricopa County Sheriff's Office knows about what's going on, but is not moving to stop it.

"We do talk about the fact that Jodi seems to be able to reach out into the community in various ways and profit from her notoriety. We don't like it... but there is nothing we can do about it," said Lisa Allen, MCSO spokesperson.

Jodi has not been convicted, which means the sheriff's department can't stop her from selling her artwork.

Her attorneys know she is tweeting, and apparently they aren't very happy about it.

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