FORT LAUDERDALE, Fla. – The suspected shooter who killed 17 people and injured more than a dozen others Wednesday at Marjory Stoneman Douglas High School is now in the Broward County jail.
Nikolas Cruz, 19, was booked into the jail in Fort Lauderdale shortly before 6 a.m. Thursday. He faces 17 counts of premeditated murder.
Broward County Sheriff Scott Israel told reporters Thursday that his office will do everything possible to ensure that Cruz "is convicted of all charges and that justice is served."
Israel said Cruz, who had been expelled from the Parkland high school, used an AR-15 rifle in the shooting and was equipped with multiple magazines.
A total of 18 shooting victims were taken to area hospitals.
Broward Sheriff's Office spokeswoman Veda Coleman-Wright said the victims were taken to Broward Health North, Broward Health Medical Center, Broward Health Coral Springs and West Boca Medical Center. She said two of the victims died at the hospital.
Local 10 News reporter Samantha Bryant said two patients have since been discharged from West Boca Medical Center and Broward Health Coral Springs.
Dr. Evan Boyar, medical director of Broward Health North's Department of Emergency Medicine, said the suspect was among those treated at the hospital before he was released back into the custody of law enforcement.
Two law enforcement officials told ABC News that the AR-15 was legally purchased by Cruz within the past year from a federally licensed dealer. All the paperwork was in order and appropriate procedures were followed, the sources said.
Authorities and school officials did not immediately say why Cruz had been expelled from the school, but a student who had a class with him last year told Local 10 News that he got into trouble after bringing a weapon on campus.
"I heard that he wasn't allowed to bring a backpack to school because they found a weapon in there, so ever since that day, he would bring a plastic bag," she said.
The teenager said she told her parents last year that she was afraid of Cruz and that he would tell his peers that he wanted to join the military so he could shoot people.
Israel said several "copycat threats" were made Thursday morning at other Broward County schools. He said deputies are investigating every "fake" threat and will charge those accordingly.
Robert Lasky, FBI Special Agent in Charge of the Miami Division, said Thursday that the FBI received information last year about a school threat made on a YouTube comment.
"The comment simply said, 'I'm going to be a professional school shooter,'" Lasky said. "No other information was included with that comment, which would indicate a time, location or true identity of the person who made that comment."
Lasky said the FBI was unable to identify who made the remark.
Two law enforcement officials and a witness said Cruz was able to leave the school after the shooting by blending in with other students who were trying to escape.
President Donald Trump issued a proclamation honoring the victims of the Parkland school shooting, ordering flags to be flown at half-staff at the White House and all public buildings. Trump also said he is making plans to visit the school.
So many signs that the Florida shooter was mentally disturbed, even expelled from school for bad and erratic behavior. Neighbors and classmates knew he was a big problem. Must always report such instances to authorities, again and again!
— Donald J. Trump (@realDonaldTrump) February 15, 2018
Broward County Public Schools Superintendent Robert Runcie acknowledged two heroes "who gave their lives" to protect the students -- athletic director Chris Hixon and assistant football coach Aaron Feis.
Runcie said the school district is offering counseling services for students, teachers and parents.
Florida Attorney General Pam Bondi said the state would pay for funeral expenses.
Marjory Stoneman Douglas High School will remain closed through Friday. All school activities are also canceled for the week. Broward County Public Schools officials said nearby Westglades Middle School will be open for the rest of the week, but grief counselors will be at the school for students and staff as needed.
The FBI has established a tipline following the shooting. Anyone with information about the Parkland school massacre is asked to call 1-800-Call-FBI.