A driver, who was 21, died a few days after the car crash that killed her sister, authorities said. (iStock/iStock)

The driver involved in a crash in Charles County, Md., that killed her teenage sister has died of injuries from the incident, authorities said.

The county sheriff’s office said Nadia Mourtaj, 21, of Waldorf, died Wednesday at a hospital after being critically injured in the Dec. 31 crash.

She was driving north on St. Charles Parkway near Gateway Plaza in the Waldorf area when the car went out of control, the sheriff’s office said.

Her sister, Zeyneb Mourtaj, who was a passenger, died at the scene, according to the sheriff’s office. An 18-year-old relative who was also in the car suffered a broken arm, the sheriff’s office said.

The incident was reported earlier this week to remain under investigation.