PLEASANTON -- A 20-year-old Galt woman has been arrested on suspicion of driving under the influence in connection with a fatal Aug. 18 crash on the Bernal Avenue exit of Interstate 680.

However, according to the Alameda County District Attorney's office, no charges have been filed yet, as the case remains under investigation.

According to the California Highway Patrol, Megan Emslander, 20, was arrested on the day of the crash that killed her sister, Samantha Emslander, 22, of Galt.

Emslander was pronounced dead at the scene of the solo-vehicle accident, according to the CHP and the Alameda County Coroner's office.

The pair were traveling in a convertible that crashed into a ditch at about 12:20 a.m.on the side of the Bernal Avenue on-ramp, authorities said.

Initial investigations by law enforcement indicated the driver may have fallen asleep behind the wheel.

Contact Katie Nelson at 925-847-2164 or follow her at Twitter.com/katienelson210