An 18-year-old Arlington, Texas high school student was allegedly shot to death Wednesday afternoon by one of his peers, prompting a lockdown and investigation, police said.

Etavion Barnes, a student at James Bowie High School, died after being found by school resource officers "lying unresponsive on the ground," the Arlington Police Department said in a news release.

Police received reports of shots being fired around 2:50 p.m. near a portable building on campus, according to the department. School resource officers initially found Barnes and attempted to perform live-saving measures until paramedics arrived, police said.

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'Please do not come to the school': Shooting prompted lockdown

Bowie High School was placed on lockdown "immediately," according to the department.

The high school subsequently shared a post on Facebook saying, "Bowie HS is on lockdown. APD is on the scene. Please do not come to the school."

Arlington police officers began searching for the alleged shooter after securing the area around the high school, the department said. They found the 17-year-old nearby and took him into custody without incident, according to the release.

The 17-year-old was booked into Arlington City Jail and charged with one count of murder, according to inmate records.

Victim and alleged shooter 'knew each other,' police say

Detectives are unclear about a motive but confirmed the alleged shooter and Barnes both attended Bowie High School and knew each other.

Once police took the 17-year-old into custody and secured the crime scene, officers began working with the Arlington Independent School District to lift the lockdown and move all students and staff to a reunification center so they could meet their families, according to the release.

"Our hearts are with the entire Bowie High School community tonight,“ Chief of Police Al Jones said in the release. “We, as a community, cannot tolerate this kind of violence. Not in our neighborhoods and not in our schools. Violence is never the right answer. We will continue to work in lockstep with our partners at Arlington ISD to ensure our schools are safe spaces where students can learn."

Bowie High School cancels classes for students on Thursday

Bowie High School announced Wednesday in a Facebook post that it would cancel classes for students on Thursday.

"When students return, they will have the full support of Arlington ISD's counseling team," the post said.

The high school communicated with parents throughout the lockdown on its Facebook page, including telling them when the shooting happened and when all students inside the building were deemed safe.

Bowie High School alumni offer prayers

Underneath the updates on Facebook, concerned alumni offered their sympathies and prayers to Bowie High School and Barnes.

Chyna Littleberry, who claims to be a graduate of Bowie High School, said in a comment, "I'm praying for everyone involved! Us volunteers believe in faith!" In a subsequent post on her own Facebook page, Littleberry wrote, "Our kids aren't safe in school! As a graduate of Bowie, my heart goes out to all of those involved. That baby died and I'm uneasy!"

Scott Marcum, who claims to have graduated from Bowie High School in 1997, said in a comment under one of the updates, "Please keep everyone that has been impacted by this incident in your thoughts and prayers and be there to support each other as everyone deals with this the best way they can."

Zachary White, another Bowie High School alumni, said in a comment, "This is extremely saddening. All y’all: the victims, the parents, (the) students, and all the staff will be in my prayers."