UVALDE, Texas -- The principal of Robb Elementary School in Uvalde, Texas is under fire.
Mandy Gutierrez was placed on administrative leave earlier this week.
Speaking to CNN, she responded to a Texas House Committee investigation that accuses her school of having a "culture of non-compliance" with keeping doors locked at all times.
According to Gutierrez, a custodian checks all classroom locks every night.
She also said a rock kept next to a door to the outside is only used to prop it open when large numbers of students are entering under adult supervision, CNN reported.
The shooter used that door to enter the school and kill 21 people, including 19 students.
It wasn't propped at the time but it wasn't locked, either.
Gutierrez denies safety protocols were routinely ignored at her school.
"I believe that everybody's at a different level in their grieving process. I believe they're entitled to their opinion. I feel that I followed the training that I was provided with to the best of my abilities and I will second guess myself for the rest of my life. But again, there's things that could change that are not in my circle of control," she said.
When asked if she feels she shares some responsibility, Gutierrez said, "I believe that there is always room for improvement. I believe that I did my job to the best of my abilities. I believe that as the campus principal, if I did the job to the best of my abilities, then I would hope that I, nobody says that I am fully responsible for what occurred that day."
Investigators also found some teachers didn't receive a warning a gunman was in the school.
Gutierrez used a phone app called Raptor to alert them. She said using the intercom could have instilled panic and alerted the gunman to the knowledge of his presence.
However, parts of the school have poor Wi-Fi reception and many teachers never received the alerts.