4 people were injured in a shooting at a high school in Arlington, Texas

• Police said four people were injured in a school shooting in Arlington, Texas, on Wednesday.
• Three of the victims were transported to the hospital, Assistant Chief Kevin Kolbye said.
• Police apprehended an 18-year-old student who turned himself in with help from his attorney.
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Multiple people were injured in a school shooting Wednesday morning at Timberview High School in Arlington, Texas, police said.

Kevin Kolbye, the Arlington Police Department's assistant chief, said there were four victims in total from the shooting. He said three of the victims were taken to the hospital and the other victim refused treatment.

Police said in a press conference that three of the victims were students and one was an older person, though it's unclear if the latter victim was a teacher or other staff member.

The oldest victim, who Dallas News identified as a 25-year-old, is reportedly in "good condition" along with one other victim. One student, a 15-year-old, is in "critical condition," according to the publication.

Kolbye said the working narrative at the moment is that the shooting occurred after a fight broke out between students on Wednesday morning.

The assistant chief told reporters that authorities had identified one suspect, Timothy George Simpkins , 18. After hours of searching, police confirmed they apprehended Simpkins after he turned himself in with the help of his attorney.

The Mansfield Independent School District said in a letter to parents on Wednesday morning that students were on lockdown and police were responding to the situation.

In another letter, the school district said an "all-clear" was given and students were being reunited with their families.

A woman on Twitter said her daughter sent her this video from the scene:

This story is developing. Please check back for updates.