Erik Menendez and his brother, Lyle, have spent more than 35 years prison for killings their parents in 1989 in a case that over the past year has gained renewed public attention following the release of Netflix's "Monsters: The Lyle and Erik Menendez Story" and various documentaries.

Erik Menendez has been hospitalized with kidney stones, according to his lawyer – who called for the release of the famed parent killer ahead of his August parole hearing. “It’s a serious condition,” his attorney Mark Geragos told TMZ of his 54-year-old client’s diagnosis.

Erik Menendez, 54, is in the hospital and has been diagnosed with a serious medical condition, his family confirmed to ABC News.