By Pete Demetriou

LOS ANGELES (CBS) — The stirring notes of classical opera were heard inside the walls of an unusual venue on Friday : a Southland juvenile detention facility.

KNX 1070’s Pete Demetriou reports while the singers and music came from outside the walls, the lyrics came from those who have served time inside.

READ MORE: Police Dog Reportedly Bites 5-Year-Old Boy In Head

Los Angeles Opera baritone/composer Eli Villanueva, mezzo soprano Nandani Sinha, baritone LeRoy Villanueva and pianist Daniel Faltus performed at Central Juvenile Hall as part of a program that brings artists to the facility to give surprise performances of poems written by the minors.

Those minors did not know their poems secretly chosen by the musicians and arranged into separate classical music pieces until the actual performances.

Villanueva sang “Free At Last”, an original composition set to lyrics written by Alton Petrie, who until recently was inside Juvenile Hall.

READ MORE: LAPD Officer Suspended After Resisting Arrest By Ventura County Deputies

Petrie was among a group called Inside/Outside Writers that educates young people on how to become songwriters, poets, screenwriters, and other disciplines.

The performance may have even inspired Petrie to change his focus and how he sees his future as a songwriter.

“I would have thought of hip hop or R&B or something, but never in one day would I have thought opera,” he said.

MORE NEWS: Astros Face Booing Dodgers Crowd For First Time Since Cheating Scandal

Each minor whose poetry was chosen as a performance received the sheet music of their poem signed by the performers.