Netflix Series Put Menendez Brothers Back in Spotlight Behind Bars

Erik and Lyle Menendez may have been badly beaten and broken in their early days of prison, before falling into relative obscurity in recent years ... but, all that changed when Ryan Murphy and Netflix got involved with their story.

A source in the California Department of Corrections tells TMZ ... when "Monsters: The Lyle and Erik Menendez Story" came out in the fall, the brothers became high profile inmates again.

We're told their prison pod was buzzing with excitement when it looked like they were definitely getting out of prison, when former Los Angeles County District Attorney George Gascón was still in charge ... though the November election of Nathan Hochman has dampened the celebratory mood.

All of this sits in stark contrast to their early days in prison ... when Erik was repeatedly beaten by other inmates -- though he told us on the "2 Angry Men" podcast he never fought back against his attackers.

Erik and Lyle were in different prisons for the first two decades of their incarceration ... Erik also told us he vividly remembers getting the news someone broke Lyle's jaw -- though he couldn't go to see him.

Now, they're locked up together in Richard J. Donovan Correctional Facility in San Diego ... and, and we hear "no violence has befallen them" since their move -- that, combined with being the toast of the cell block, is vastly different from the brothers' early days.

After the TV series dropped, attorney-in-training Kim Kardashian, who met with the brothers in prison, declared they "are not monsters" ... describing them as "kind, intelligent and honest men" who should have their life sentences reconsidered.

Of course, not everyone is pulling for Team Menendez inside the joint ... 'cause there are haters who always talk trash due to their jealousy about the brothers' newfound status and their prospect of getting out ... which creates obvious tension.

But, the Menendez bros have commissary money, new hope for release ... and each other.

Lyle even talks to his new girlfriend -- Milly Bucksey -- almost daily via video chat ... another connection he didn't have when they were first incarcerated decades ago.