UPDATE 3:17 p.m. -Timothy George Simpkins has been detained on a $75,000 bail.

UPDATE 1:38 p.m. – Gov. Greg Abbott released a statement on the shooting.

“As law enforcement continues their investigation, our hearts go out to the victims of this senseless act of violence. Thank you to the law enforcement officers and first responders who arrived on the scene to help the victims and prevent further violence. I have spoken with the Mayor of Arlington and offered any assistance the state can provide, and I have directed the Texas Department of Public Safety to make state resources available to help bring the criminal to justice. I ask all Texans to join Cecilia and me in praying for the victims, their families, and the entire Timberview High School community.”

UPDATE: 1:29 p.m. – The suspect, Timothy Simpkins, is in custody.

He will be charged with three counts of aggravated assault with a deadly weapon.

All students have been evacuated from the school and the search of the building is complete, police said.

Officials recovered a .45 caliber handgun from the streets in Grand Prairie. The weapon will be turned over to ATF. Police cannot confirm that this was the weapon used in the shooting, but they believe it could have been.

Officials say there is no threat to the public at this time.

UPDATE 1:07 p.m. – There is now more information available about the victims of Wednesday’s shooting.

A 15-year-old male student was shot and is in critical condition.

A teenage female suffered a “small abrasion” and is considered to be in good condition.

A 25-year-old male was taken to the hospital and is also said to be in good condition. The nature of his injury is not yet known.

The fourth person, a pregnant woman, was treated and released at the scene.

UPDATE 12:41 p.m. – A teenager was confirmed to have been brought to Medical City Arlington after the school shooting.

UPDATE: 12:40 – In a neighborhood about a mile away, US Marshals are standing outside a residence.

They have confirmed that the situation in the neighborhood is connected to the school shooting.

Arlington PD and US Marshals have a few blocks blocked off for the situation.

UPDATE 12:22 p.m. – Texas Lt. Gov. Dan Patrick issued a statement on the shooting:

“Texans are heartbroken and outraged by news of the shooting at Timberview High School in Arlington. Please join Jan and me in praying for all the victims to make a full recovery, and for their families and friends. Please also join us in prayer for our brave law enforcement officers who put their lives on the line to protect us every day.”

UPDATE 12:01 p.m. – Mansfield ISD gave an update on the Timberview High School shooting.

Mansfield ISD said that there is one injured student and one injured staff member. This differs from information from an earlier press conference where police said they thought there were four injuries total, with two student injuries.

The district said counseling services will be available for students and parents at the reunification location at the Mansfield ISD Center for the Performing Arts.

UPDATE: 11:20 a.m. – Mansfield Police Assistant Chief Kevin Kolbye spoke to media Wednesday morning, confirming that there were four victims of the shooting and a suspect is at large.

One of the victims, a pregnant woman, was reported to have fallen and was treated at the scene. Three others were taken to the hospital, at least two with gunshot wounds. Of the four injured, two are thought to be students.

Police identified the suspect as 18-year-old Timothy George Simpkins. Police said they believe a fight between Simpkins and another individual in a class broke out, then a gun was used.

Simpkins is a black male and police believe he is driving a 2018 silver Dodge Charger with the license plate PFY-6260.

Multiple agencies, including US Marshals, are looking for Simpkins. He is considered armed and dangerous. If you see him, police ask that you call 911.

At 9:15 a.m., police got a call that there was a shooting on the second floor at Timberview High School.

UPDATE 11:10 a.m. – Mansfield ISD has given an “all clear” to start evacuating students at Timberview High School after a shooting on campus Wednesday morning.

ARLINGTON, Texas (KETK) – Police confirmed that there are multiple injuries after a shooting at an Arlington high school.

Timberview High School went on lockdown this morning after the reported shooting. There is now a heavy police presence at the high school and an NBC 5 chopper is on the scene live.

Timberview is part of the Mansfield Independent School District.

In a statement to parents, Mansfield ISD said students and staff are still locked in their classrooms and no visitors are allowed in the building at this time.

Mansfield ISD is setting up a parent reunification point at the Center for Performing Arts at 1110 W. Debbie. Officers will be there and students will be bused to that located when the school is completely secured.

Multiple law enforcement agencies are on the scene. NBC 5 crews report seeing officers with long guns running from the parking lot into the school. Arlington PD said they are doing a methodical search of the area.

The reports of the shooting first came in around 9:20 a.m.

This story is developing. Refresh this page for updates.