If you aren't willing to take immediate action in an active shooter situation, you can be reassigned, Denton County Sheriff Tracy Murphree reminded deputies in a memo Tuesday.

"We do not stage and wait for SWAT, we do not take cover in a parking lot, and we do not wait for any other agency," he wrote. "We go in and do our duty."

The memo comes after a Florida sheriff announced that the deputy on duty at Marjory Stoneman Douglas High School when a 19-year-old opened fire, killing 17 people, never went in the school. The deputy, Scot Peterson, has since resigned.

Peterson has faced criticism from his former department, the president and people around the country. Broward County Sheriff Scott Israel said the deputy should have "went in, addressed the killer, killed the killer."

Denton County's Murphree said he wanted to make his policy on active shooter response clear in response to the Florida school shooting on Feb. 14.

"All commissioned Deputies if you respond to an active shooter, you are expected to take immediate action," Murphree wrote.

"We go in to engage and stop the shooter and save lives," he said in the memo, which was shared on Twitter with a message saying there is "NO DOUBT" where the office stands.

Just in case you were wondering. There is NO DOUBT where we stand. Denton County Sheriff's Office, BUILT ON INTEGRITY! pic.twitter.com/xYC7dmNVr3 — Denton Co Sheriff (@DentonCoSheriff) February 27, 2018

Any deputy who can't follow that directive should let their supervisor know so they can be reassigned, he said.

Murphree also spoke out after last year's bombing in Manchester at an Ariana Grande concert, saying America "better wake up" to threats of terrorism.

"This is what happens when you disarm your citizens," the sheriff wrote at the time. "When you open your borders without the proper vetting. When you allow political correctness to dictate how you respond to an enemy that wants to kill you."

He urged Americans to "do something quick," else the country "die of political correctness."

"What will it take? This happening at a concert in Dallas or a school in Denton County?" Murphree wrote in a Facebook post.

Murphree, a former Texas Ranger, took office in January 2017.