Last month, Justin Bieber made headlines when his tour RV was spotted entering L.A. County’s California State Prison.

At the time,  a representative from the California Department of Corrections and Rehabilitation said that Bieber and a pastor had been given approval to visit by the prison’s warden, in support the prison’s faith-based programs.

Now, thanks to a video obtained by TMZ, more info about Bieber’s trip behind bars has emerged.

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In the video (above), Bieber can be seen singing his hit “Lonely” to a small group of prisoners sitting on benches, accompanied by a musician playing guitar.

Sources told TMZ that Bieber performed “three or four of his songs, focusing on slower tracks that translate better with an acoustic guitar accompanying him… We’re told by people who were present that Bieber’s mini unplugged set was emotional, empathetic and had him on the verge of tears. It was well received by the inmates and followed by a sermon.”

In addition to singing, Bieber also spent some time outside in the prison yard listening to some of the inmates speak.

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The same day as his prison visit, Bieber took to social media to share a message of faith.