By Ian Simpson

(Reuters) – A 16-year-old girl critically wounded this week by a fellow student at a Maryland high school has died, raising the number killed in the latest deadly U.S. school shooting to two, authorities said on Friday.

Jaelynn Willey died at 11:34 p.m. EDT on Thursday, surrounded by her family, the St. Mary’s County Sheriff’s Office said in a statement on Friday.

The death came hours after her mother said at a hospital that her daughter had been declared brain dead and would be taken off life support.

“It is with heavy hearts and great sadness we provide this update,” the sheriff’s statement said.

Willey, a student at Great Mills High School in southern Maryland, was shot by student Austin Rollins, 17, in a hallway on Tuesday. Willey had been in a relationship with Rollins that had recently ended, the sheriff’s office has said.

A school resource officer confronted Rollins and they simultaneously fired shots at each other, according to police. Rollins was wounded and died at a hospital. The officer was unharmed.

Investigators have been uncertain over who fired a shot that hit a 14-year-old student in the leg.

(Reporting by Ian Simpson in Washington; Editing by Jonathan Oatis)