Julia Roberts
Nancy Motes, the half-sister of actress Julia Roberts (pictured), was found dead on Sunday. Her family believes she died of a drug overdose although a coroner has still not determined her cause of death. Reuters

The death of actor Julia Robert’s half-sister, Nancy Motes, is under investigation in Los Angeles, although the family believes Motes died of a drug overdose.

Motes, the younger half-sister of Roberts and her brother, actor Eric Roberts, was 37 years old. In a statement sent to People magazine, her family said she died Sunday “of an apparent drug overdose.” Motes has the same mother as Eric and Julia Roberts.

"It is with deep sadness that the family of Nancy Motes ... confirms that she was found dead in Los Angeles yesterday of an apparent drug overdose," read the statement, which was sent Monday to People. "There is no official report from the Coroner's office yet. The family is both shocked and devastated."

Ed Winter, the assistant to the Los Angeles County Coroner, told CNN that paramedics were called to a Los Angeles home, which was not Motes’s residence, after she was found on the floor of a bathroom. Winter said Motes was pronounced dead at the scene, and he indicated that drugs may have played a role in her death.

"She has a history of some medical issues," Winter told the network. "Some prescription drugs were found near her body."

Los Angeles County Coroner spokesman Capt. John Kades told Reuters that Motes’s body was found in a bathtub full of water. Suicide has not been ruled out, Kades said, adding that a suicide note may have been found in the home.

An autopsy on Motes’s body was scheduled for Tuesday. But results on Motes’s actual cause of death may not be known until eight to 10 weeks, Reuters reported.

In the weeks before her death, Motes reportedly tweeted about her frayed relationship with her half-sister, according to Fox News. The tweets have since been deleted.

In one of the posts, tweeted in October, Motes expressed how excited she was for her upcoming wedding.

"It's a shame when you get more support from strangers than you do from your family. I can't wait to officially belong to another family!" Motes wrote.