The teenage boy who opened fire inside his Maryland high school on Tuesday used his father's gun to shoot his ex-girlfriend and another student, authorities say.
The handgun that the shooter -- identified by authorities as 17-year-old Austin Wyatt Rollins -- used was legally owned by his father, the St. Mary's County Sheriff's Office said in a statement issued Wednesday afternoon.
Rollins "had a prior relationship which recently ended" with the 16-year-old girl who he gravely wounded, the sheriff's office said.
"All indications suggest the shooting was not a random act of violence," the statement said.
The investigation has not yet revealed any threats from Rollins.
A 14-year-old boy shot in the leg at Great Mills High School in St. Mary's County had been released from a hospital as of noon, hospital officials said. The 16-year-old girl remains in critical condition.
The violence erupted moments before classes started on Tuesday. It wasn't immediately clear whether Rollins took his own life or was killed by a school resource officer's bullet, nor was it clear how the 14-year-old boy was wounded, St. Mary's County Sheriff Tim Cameron said.
Authorities didn't release a motive.
Police did not identify the victims, but the family of 16-year-old Jaelynn Willey, a sophomore at Great Mills, confirmed she had been shot.
Willey is one of nine siblings, according to a statement from the family, and a member of the swim team. She is a role model to her brothers and sisters, her family said, and helps to take care of them every day.
Earlier Tuesday, law enforcement was set to complete an urgent trace request by the sheriff's office for the history of the semi-automatic Glock handgun that officials say Rollins used.
The Bureau of Alcohol, Tobacco, Firearms and Explosives tries to answer such requests within 24 hours. Specifics would include the make, model and serial number of the firearm.
"The purpose of a trace is to find out who the initial purchaser of a firearm is," said Amanda Hils, a spokeswoman for the Baltimore field division
However Rollins got the gun, it appeared he possessed it illegally. In Maryland, a person must be 21 to possess a handgun, unless carrying one is required for employment.
Great Mills High will be closed for more than a week and a half, after the school's scheduled spring break. Classes will resume April 2, the principal said in an online notice to families.
"Words cannot express the sadness and grief that our school community is feeling right now. I know that we are shaken and scared after today’s events and will struggle for some time trying to make sense of it all. I do not know exactly how, but we will find a way to overcome this tragedy," the notice said. "Now more than ever, we need to stand together as a school community to love, cherish, and support one another. We have and we will continue to stay strong, stay together, and find a way to get through this."
Counseling services are being offered.
Before they return to class, many students and school alumni plan to participate in Saturday's March for Our Lives in D.C. Thousands of people are expected to attend the demonstration, which was organized after the Feb. 14 shooting at Marjory Stoneman Douglas High School in Florida that left 17 students and staff members dead.
A student witness of the shooting said a police officer tried to order a student with a gun to his head to disarm before two shots were fired.
Student Isiah Tichenor told The Washington Post he saw a fellow student hold a gun to his head Tuesday and heard a police officer shout an order to put the gun down.
Attempts to reach Rollins' family were unsuccessful.
One of the shooter's friends, 14-year-old Jordan Hutchinson, and his mother dropped off a condolence card at the Rollins home.
Jordan recalled meeting Austin five years ago during a snowstorm, and building snow forts together.
"Austin was a nice kid. We did sleepovers all the time," he said.