The family of an 18-year-old student suspected of opening fire and injuring four people at a Texas high school on Wednesday claims he was being bullied and brought the handgun to protect himself.

Timothy Simpkins, a student at Timberview High School in Arlington, allegedly drew a .45-caliber handgun during a fight that broke out in a classroom around 9:15 a.m. before fleeing in a 2018 Silver Dodge Charger. After an hourslong manhunt, Simpkins turned himself in and is expected to be charged with three counts of aggravated assault with a deadly weapon.

He was released from Arlington police custody Thursday after posting a $75,000 bond. He faces three counts of aggravated assault with a deadly weapon.

TEXAS HIGH SCHOOL SHOOTING INJURES MULTIPLE, SUSPECT IN  CUSTODY, ARLINGTON POLICE SAY

Simpkins walked quietly out of the jail as reporters followed him. He walked to the Pretrial Release Department so he could be fitted with an electronic leg monitor and receive the conditions of his bond, Fox affiliate KDFW-TV reported. 

Following the incident, Simpkins’ family told reporters outside their home in Arlington that he was a target of bullying and had been robbed twice at school.

"The decision he made, taking the gun, we are not justifying that. That was not right. But he was trying to protect himself," said family member Carol Harrison Lafayette, according to the news outlet. "We hope the police department does the investigation properly."

Timothy Simpkins turned himself in after an hourslong manhunt and is expected to be charged with three counts of aggravated assault with a deadly weapon. (Arlington Police Department)

"To the victims' family, there is no justification of anybody being hurt," Lafayette said.

A 15-year-old boy was shot and remained in critical condition while a 25-year-old teacher who was also shot was in good condition, the outlet reported. A teenage girl was treated and released from a hospital after being grazed by a bullet. A pregnant teacher was injured in a fall and was treated at the scene. 

Families depart the Mansfield ISD Center For The Performing Arts Center where families were reunited with Timberview High School Students on Wednesday in Mansfield, Texas. (AP Photo/Tony Gutierrez)

Lafayette said that Simpkins had been targeted for wearing nice clothes and driving a nice car, the Fort Worth Star-Telegram reported, adding that incidents between Simpkins and other students had been reported to principals and teachers.

Arlington Police Department Assistant Chief Kevin Kolbye said weapons were found during a search of the Simpkins family home, including the one believed to have been used in Wednesday's shooting. He said a weapon found on the street in Grand Prairie, Texas has been linked to the suspected handgun. 

"ATF has done forensics and has matched that weapon with the casings that were found in the school," Kolbye said on "Good Day." "We are at a high confidence degree we have found the weapon that was used."

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Arlington police said cellphone video shows the fight breaking out before Simpkins fired the gun. Lafayette claimed the video shows Simpkins was being attacked, the paper reported.

An arrest affidavit obtained by the news station said a witness tried breaking up a fight involving Simpkins. 

"The witness was able to control the other individual involved in the altercation," the document said. "This individual gave up and stopped being combative. When the witness turns around to check on Simpkins, Simpkins had produced a firearm."

Kolbye said the bullying claims will be investigated and warned the Mansfield Independent School District to "reevaluate some of their safety measures."

"I will tell you, that over the past few years, we have seen an increase in our youth, in Arlington and other cities too, carrying weapons," he said. "And we just can’t stress enough that today, young people carrying weapons is just not a solution to any type of violence or anything like that."

All classes and after-school activities were canceled Thursday, and counseling services were made available for students, staff and families.

Fox News’ Danielle Wallace contributed to this report.