Julia Roberts' half-sister ripped the actress and wrote that her family "abandoned" her in the weeks leading up to her death on Sunday, according to the New York Daily News.

Nancy Motes, 37, was found dead Sunday in a bathtub at a Los Angeles home where she was pet-sitting. The News reported authorities found evidence of drug use.

Motes reportedly struggled with her weight for years, while having a rocky relationship with her Academy Award-winning sister, who canceled a scheduled appearance on "Jimmy Kimmel Live" and skipped an Academy Award luncheon on Monday. Roberts was doing promotional rounds for her latest film, the Oscar-nominated "August: Osage County."

Authorities were called to the house about 2 p.m. Sunday after Motes' body was found by John Dilbeck, a film and TV locations manager whom she was supposed to marry in May, a law enforcement source told the Daily News. The source said police suspect a drug overdose.

Motes sounded despondent on Twitter during the weeks before her death.

She tweeted on Jan. 19, "So my 'sister' said with all her friends & fans she doesn't need anymore love. Just so you all know, 'America's Sweetheart' is a (expletive)."

On Jan. 22, she tweeted "(M)y own family has abandoned me."

Craig Harvey, chief of coroner investigations for Los Angeles County, told The News that Motes "was found in a bathtub that contained water. There were prescription and nonprescription drugs found at the scene. The role the drugs may or may not have played is not yet known."

An autopsy was scheduled for Monday, but Harvey said additional toxicology tests would likely be needed to determine a cause of death.

The law enforcement source told The News that Motes didn't leave a suicide note. "There was no evidence of foul play, no note, nothing like that," the source said. "It's too soon to say that it was a suicide."

Contact Tony Hicks at Facebook.com/BayAreaNewsGroup.TonyHicks or Twitter.com/insertfoot.