The San Bernardino school had police patrols, tighter security and additional support staff.
Starting this week, visitors will only be allowed on campus once they're buzzed in through a new video-monitoring system at the secretary's desk, where staff can question the visitor to determine whether to grant access.
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In addition to the buzzer, North Park installed a system that will enable officials to take photos of visitors and then print out an ID badge.
"We will not allow the actions of one individual to interrupt our commitment and our resolve to our students, families, faculty and staff," said Dale Marsden, superintendent of the San Bernardino City Unified School District.
Students, parents and staff members were wearing red, the school color, to show strength and solidarity.
Many of the parents said their children were looking forward to come back to school.
"They're coping. The first couple of days were very hard, especially for my daughter, but my children now are very excited. They want to come back to school. They want to see their teachers," said Juan Rubalcava, a parent.
Though most of the students were excited to return to school and see their friends, emotions were still raw. Even within the community, the wounds will be slow to heal.
Area resident Jason McLeod brought teddy bears to campus for the children on their first day back in class.
"This is for the little guys in heaven. This is for the little guys that don't have nothing...it's just sad," McLeod said.
North Park has been closed since April 10, when Cedric Anderson walked into the classroom of his estranged wife Karen Smith and opened fire, killing her and 8-year-old student Jonathan Martinez.
Anderson then fatally shot himself.
Nine-year-old student Nolan Brandy was also wounded in the shooting but survived. He was released from the hospital on Friday.
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Classroom B-1, where the shooting took place, has been sealed off. Many of the students from Smith's class will be moved to a new room, C-1, and they already know their new teacher.
As students walked up to the school's entrance, they were greeted by messages of encouragement written by students from another elementary school. Also, a bubble maker drove in from San Diego to help spread joy.
In addition to the teddy bears McLeod brought, students were also greeted by thousands of unexpected furry friends. A Cal State San Bernardino worker, Stacy Brooks, collected 3,000 teddy bears through a toy drive to help students heal.