This story is part of a KXAN series of reports called “Stop Mass Shootings,” providing context and exploring solutions surrounding gun violence in the wake of the deadly Uvalde school shooting. We want our reports to be a resource for Texans, as well as for lawmakers who are convening a month after the events in Uvalde to discuss how the state should move forward. Explore all “Stop Mass Shootings” stories by clicking here.

Editor’s Note: On Thursday, the Department of Public Safety clarified a Uvalde ISD officer was not on campus and was not the first member of law enforcement to confront the shooter.

UVALDE, Texas (KXAN) – The shooter who killed at least 19 children and two teachers at Robb Elementary School on Tuesday walked into the school without being stopped by anyone, the Texas Department of Public safety said Thursday. It corrected a statement Wednesday by DPS Director Steven McCraw that a Uvalde ISD police officer was the first person to engage the shooter. Instead, on Thursday it said there were not Uvalde ISD police on campus.

“The reason it was not worse is because law enforcement officials did what they do. They showed incredible courage running towards gunfire trying to save lives,” said Texas Gov. Greg Abbott Wednesday.

Uvalde CISD, located 84 miles outside of San Antonio, is one of the smaller school districts in Texas. The school district has its own police department made up of four officers, a police chief and a detective. According to the school’s website, the district has also hired a security guard.

The district’s policy is to have security staff patrol door entrances, parking lots, and the perimeters of campuses at the middle and high school, according to a document listing the school district’s security measures from the 2019-20 school year.

It is unclear if Uvalde CISD typically stations its police officers at the elementary school campus.

The National School Safety and Security Services President Kenneth Trump said it is ideal to have a licensed, commissioned officer stationed on school campuses, but said, in reality, the practice is economically and logistically challenging for school districts.

“These incidents unfold in seconds and minutes. It helps to have a trained commissioned school police officer on campus when you can. The reality is manpower and budgets and costs across the country prohibit that, particularly at elementary schools,” said Trump.

Trump says even those school districts that have school-based police officers or school police departments typically place the officers at the upper-school level — middle schools and high schools. The districts usually share those officers with elementary schools, when needed.

“The challenge we have is that every minute counts. Law enforcement response, in this case, was highly effective and timely, but we need to train our school staff on everything they can do to buy time until that law enforcement response is on site,” said Trump.

The 2019-2020 Uvalde ISD list of preventative security measures stated the district’s high school utilized a security vestibule and outside door buzz-in system. It also stated teachers are instructed to keep their classroom doors closed and locked at all times.

The TEA released a list of recommended actions it wanted Texas school districts to address before the start of the 2018-19 school year, including the option to train select school employees to be armed school marshals.

There are currently 62 school districts using trained school marshals and 256 active school marshals across the state. The number of marshals in each district is confidential, according to data provided by the Texas Commission on Law Enforcement.