A teenage girl who was shot when a classmate opened fire inside their high school in Maryland has died, authorities said.
Jaelynn Willey died at 11.34pm local time on Thursday, St Mary's County Sheriff's Office said.
Earlier that night, her family said she would be taken off life support at the University of Maryland Prince George's Hospital Centre.
Melissa Willey told news reporters on Thursday night that her daughter was brain dead and had "no life left in her".
The mother, holding a young baby, said: "On Tuesday ... our lives changed completely and totally forever. My daughter was hurt by a boy who shot her in the head and took everything from our lives."
The teenager was shot on Tuesday by 17-year-old Austin Rollins at Great Mills High School in St Mary's County.
Rollins died after shooting Jaelynn.
A school resource officer got there within a minute and fired a shot at Rollins, but it is not yet clear whether Rollins was killed by the officer's bullet or took his own life.
Rollins and the girl had been in a relationship that recently ended, St Mary's County Sheriff's Office said on Wednesday.
"All indications suggest the shooting was not a random act of violence," police said in a statement.
Jaelynn was one of nine siblings, her mother said, and a member of the swimming team.
The shooting broke out just before classes were to begin on Tuesday, according to the sheriff's office, which said the gun used belonged to Rollins's father.
Desmond Barnes, 14, who was shot in the thigh during the encounter was released on Wednesday from hospital.
His mother Kimberly Dennis said her family is "eternally grateful" that her son is "alive, doing well and in good spirits".
Great Mills High School has about 1,600 students and is near the Patuxent River Naval Air Station, about 65 miles south east of Washington.
St Mary's County Sheriff Tim Cameron credited Deputy First Class Blaine Gaskill with preventing any more loss of life.
Mr Cameron said Mr Gaskill, a six-year veteran with Swat team training, responded within a minute and fired his weapon simultaneously with a final shot fired by Rollins. The officer was unharmed.
On Wednesday, authorities said the Glock handgun used in the shooting was legally owned by Rollins's father.
In Maryland it is illegal for anyone under 21 to possess a handgun unless it is required for their employment.