Erik and Lyle Menendez are currently serving life sentences without the possibility of parole for the 1989 killings of their parents, Kitty and Jose Menendez.

The hearing will determine whether they should receive a lesser sentence, which could lead to paroled release.

The two-day proceeding could end with a reduction in their sentence that would be a major win for the siblings jailed for their parents' 1989 murders.