(CNN) -- Principal Dawn Hochsprung, killed in Friday's shooting at her Connecticut elementary school, recently installed a new security system to ensure student safety.
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In a letter this fall to parents at Sandy Hook Elementary School, Hochsprung said that every visitor would be required to ring the doorbell at the front entrance after the doors locked at 9:30 a.m.
Staff began a visual monitoring system to determine entry.
Parents and visitors then had to report directly to the main office and sign in. Parents would also be asked for photo identification if staff didn't recognize them.
In a letter addressed to "Members of our Sandy Hook Family," she asked parents to be patient with the school district's new system in all elementary schools.
"Please understand that with nearly 700 students and over 1,000 parents representing 500 SHS families, most parents will be asked to show identification," Hochsprung wrote.
On Friday, the district's webpage featured a gallery of school photos with the caption "Safe School Climate."
In 2010, a community newspaper profiled Hochsprung as one of the Newtown School District's new principals. She entered Sandy Hook Elementary with 12 years of administrative experience, and she had recently been a principal at Regional School District 14 serving the Connecticut communities of Bethelem and Danbury, the Newtown Bee said.
She had also worked as an assistant principal in the Danbury, Connecticut, Public Schools District, the paper said.
Hochsprung, of Waterbury, Connecticut, was raising two daughters and three stepdaughters, and she was excited about becoming Sandy Hook's new principal, she told the newspaper.
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"I don't think you could find a more positive place to bring students to every day," Hochsprung told the Newtown Bee.
In her letter about the new security system, Hochsprung said glitches would be inevitable, and parents may have to wait to be buzzed inside the school because office staff is often busy on the phone, in the copy room or handling student concerns.
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"Though they will work diligently to help you into the building as quickly as possible, there may be a short delay until someone can view you on the handset and allow you to come in electronically," Hochsprung said.
"We continue to encourage and value your presence in our classrooms and are counting on your cooperation with the implementation of this safety initiative," she wrote.
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As Sandy Hook principal, she maintained an active Twitter account, posting messages and photos about possible new books and a student rehearsal for a fourth-grade winter concert.
"Setting up for the Sandy Hook nonfiction book preview for staff ... Common Core, here we come!" she wrote on Thursday, her most recent tweet. A photo depicted several children's books, including "Alligator or Crocodile? How Do You Know?"
Another photo shows a choir of boys and girls dressed in white shirts and black pants or skirts being led by the music teacher. The audience was all students.
"Sandy Hook students enjoy the rehearsal for our 4th grade winter concert - a talented group led by Maryrose Kristopik!" Hochsprung tweeted Wednesday. Kristopik is listed as music teacher on the school's website.
Hochsprung received a bachelor's degree in special education from Central Connecticut State University in 1993 and a master's degree in special education from Southern Connecticut State University in 1997, according to the News-Times of Danbury, Connecticut.
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