This is not a new problem, including in the United States, but it is highlighted in this story from Breitbart.

An excerpt.

One of the terrorists who murdered Fusilier Lee Rigby is radicalising other prison inmates who vow to become jihadists when they are released, prison sources have revealed.

Sources at Her Majesty’s Prison Frankland have told The Mirror that Michael Adebolajo, who along with fellow Islamist Michael Adebowale, murdered and attempted to behead Fusilier Lee Rigby near Woolwich Barracks in 2014, has already radicalised dozens of prisoners.

Non-Muslim prisoners are said to have converted under the influence of the terrorist and have sworn allegiance to Islamic State. His recruits have vowed to commit acts of terror when released, the paper reveals.

One prison official said: “Adebolajo spends most of his waking hours preaching his distorted form of Islam to anyone who will listen. He sees every inmate as a potential Islamic State soldier whether they are Muslims or not.

“He has a big personality and is very charismatic and some of the more vulnerable prisoners will fall under his spell. He is a very dangerous individual.”

The source told The Mirror that Adebolajo sees his role in life to recruit as many Jihadis as possible.

He added: “If he is suspected of trying to radicalise other inmates we step in and move him… But even in prison Adebolajo cannot be watched all the time. We don’t have the staff or the resources.”

Adebolajo was given a whole-life order excluding the possibility of parole, and Adebowale was given a minimum term of 45 years in prison.

In August 2016, a report found that political correctness was to blame for the flourishing of Islamic extremism in prisons, with guards reluctant to confront Muslim inmates for fear of being branded ‘Islamophobic’.