Menendez Brothers' Family to Hold Press Conference Asking for Resentencing

Erik and Lyle Menendez aren't just receiving support from big-time celebs like Kim Kardashian ... they've got family in their corner too, who are holding a press conference to push for the brothers' release.

According to multiple reports, about two dozen members of the Menendez brothers' family will host a press conference in Los Angeles Wednesday afternoon to pressure L.A. County District Attorney George Gascón to officially recommend resentencing the notorious killers.

Among the key pieces of new evidence the family is expected to discuss is a letter written by Erik just months before the killings ... in which he allegedly told his cousin, Andy Cano, about the abuse he and Lyle faced at the hands of their father.

Cano's mother reportedly found the letter from Erik about nine years ago. During their trial, Andy testified Erik had told him about his dad's alleged abuse when he was just 13 years old. Cano passed away in 2003.

As we told you, earlier this month D.A. Gascón held a press conference saying his office was reevaluating evidence in the Menendez case ... and the district attorney said he'd heard about the abuse claims made by Menudo bandmember Roy Rosselló.

Erik and Lyle have been locked up since 1990. They testified about the abuse they faced during their first trial, which ended in a hung jury -- but a judge refused to allow such testimony in the retrial. They're serving life sentences without the possibility of parole.