"All of our children are safe," Neilsen told reporters on Wednesday afternoon. He called the shooting a "tragedy for Placerville."
Nielsen said the shooting happend in the principal's office at Louisiana Schnell Elementary School. At least one student may have witnesses the attack.
LaCara, who was shot in the torso, was taken to nearby Marshall Hospital. He died shortly after 11 a.m., the Nielsen said.
Capt. Larry Marinas of El Dorado County Fire said the school was initially placed on lockdown while police searched for Luebbers. The campus is located at 2871 Schnell School Road.
Buses eventually arrived at the school to transport students to the El Dorado County Fairgrounds, where they were reunited with parents.
Many parents expressed frustration about conflicting information about where to pick up their children. Nielsen apologized for the confusion.
Parents said LaCara did a good job at the school. Some parents described Luebbers as "grumpy" and "rude" toward some students.
The El Dorado County Office of Education said Thursday classes at all three Placerville district schools are canceled.
Those schools are: Sierra School, Schnell School and Edwin Markham Middle School.
The staff at all three schools will meet Thursday at Markham Middle School to decide how to handle the students' return.