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API / Fame Flynet 1 / 15

Drew Barrymore's half-sister, Jessica Barrymore, was reportedly found dead in San Diego, Calif., on Tuesday, July 29, KGTV ABC10 reports. She would have turned 48 on July 31.

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According to local news, Barrymore was found inside her car at around 6 a.m. Witness Marta Lopez reportedly found the car blocking her driveway and approached the woman in the driver's seat. National City police say the cause of death is still unknown.

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"You need help, you need help," Lopez said to Barrymore, who was unresponsive. A SoBe energy drink and "dozens of white pills" were said to be found inside the vehicle.

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"Her car was parked right here last night around midnight," onlooker Oscar Sandoval told KGTV ABC10. "I thought she was sleeping or waiting for someone." The Medical Examiner's Office confirmed to 10News the victim's name and her date of birth.

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Jessica and Drew, 39, share the same father, actor John Drew Barrymore.

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