Chelsea Manning, the federal prisoner formerly known as U.S. Army soldier Bradley Manning, called out Caitlyn Jenner, formerly known as Kardashian family patriarch Bruce Jenner, in a blistering tweet from behind bars:

Caitlyn Jenner is Barbara Walter's most fascinating person of 2015

File photo

Credit: Jennifer Brett

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Credit: Jennifer Brett

The tweet generated a slew of retweets, some support and some confusion regarding how a prison in Fort Leavenworth is able to access the Internet:

Chelsea Manning's Twitter profile photo. Manning's bio reads, "Former Intelligence Analyst. Trans Woman. Prisoner. Tweets are my own opinions."

Credit: Jennifer Brett

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Credit: Jennifer Brett

Manning is serving a 35-year sentence for leaking diplomatic intelligence to the site WikiLeaks. The Army granted Manning's battle to begin gender reassignment therapy while incarcerated.

Manning has stayed busy from prison, penning this piece in the Guardian blasting "xenophobic sentiment" following the terrorist attacks in Paris and this piece in Medium lamenting "the most brutal Presidential primary season in U.S. memory."

Vanity Fair explained how Manning maintains such a robust social media presence from custody: by submitting print pieces via mail and dictating tweets over the phone.