Selena Murder

The family of "Selena" star Lupe Ontiveros is incredibly upset she was left out of last night's "In Memoriam" presentation at the Oscars ... despite appearing in dozens of major films over the past 30 years.

Ontiveros -- who passed away in July 2012 -- had roles in "Real Women Have Curves", "As Good as it Gets", and "The Goonies" ... but is best known for her role as Yolanda Saldívar, the woman who murdered Selena.

Ontiveros' son Elias tells TMZ ... the whole family gathered to watch the awards show -- and was "disappointed" Lupe wasn't given her proper due -- especially considering some lesser-known people were honored over his mom.

You'll recall, George Clooney did warn some artists might be left out when introducing the tribute, saying, "For for those friends who are on this list tonight, and many others who aren't, we thank you for the memories."

Other celebs snubbed along with Ontiveros -- Andy Griffith, director Gore Vidal, Sherman Hemsley, athlete-turned-actor Alex Karras, and Sylvia Kristel.

Yolanda Saldívar -- the woman who shot and killed Latino pop legend Selena -- doesn't plan on releasing a comment about the death of the women who portrayed her on the big screen ... because Yolanda has never seen the movie.

Yolanda -- the former President of Selena's fan club -- is currently locked up in a Texas prison ... serving out a life sentence for killing the 23-year-old singer in 1995. She was portrayed in the 1997 biopic "Selena" by Lupe Ontiveros.

After Lupe passed away this week, we reached out to Yolanda's family to see if she had any thoughts on the actress' death.

Yolanda's brother told us ... nobody in the family had ever seen the movie because they believe it's "filled with lies" about Yolanda.

Still, Yolanda's brother says the family never felt any ill will towards Lupe ... because she was an actress and was only "doing what she was told."