NBC 5 obtained new information on Wednesday’s fatal stabbing during a high school track meet in Frisco.

The attack claimed the life of Austin Metcalf, 17, of Frisco.

Jeff Metcalf, the victim’s father, told NBC 5 on Wednesday that his son was stabbed in the heart and died in his twin brother’s arms.

An arrest warrant details the moment officers arrived on scene and what witnesses say happened leading up to the deadly confrontation.

According to one of the responding officers, the suspect, Karmelo Anthony, 17, admitted to stabbing Austin Metcalf, 17, claiming self-defense.

When an officer referred to Anthony as the alleged suspect, Anthony reportedly responded, “I’m not alleged. I did it.”

According to the arrest report, the tragic event began with the suspect sitting under another team’s pop-up tent as rain fell Wednesday morning and was told to move.

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According to police, the two students, from different high schools, began fighting.

 A witness told police, Anthony unzipped a bag he had on his person, reached in, telling the victim [Metcalf]: “touch me and see what happens.”

When Metcalf pushed Anthony, witnesses say Anthony pulled a knife from the bag and stabbed Metcalf in the chest, according to the arrest report.

The murder suspect walked away before being arrested by responding officers.

Anthony reportedly asked an officer on the scene if what happened could be considered self-defense and asked if the victim was going to be OK.

Anthony is charged with murder and is in the Collin County Jail on $1 million bond.

If convicted, he faces 5 to 99 years in prison.

In a new mugshot released Thursday by the Collin County Sheriff’s Office, Anthony appeared less emotional than in the mugshot taken after his arrest on Wednesday.

Following the incident, Frisco police said Anthony, a Centennial High School student, stabbed Metcalf, a Memorial High School student, during a fight.

Frisco police and the school district declined to provide new information or interviews on Thursday.

The district’s spokesperson did not respond to questions raised by many parents online, including what kind of security was on site for the morning track meet and whether athletes’ bags are checked.         

“Frisco ISD doesn’t use metal detectors in a school, so it would be unusual for them to have them in an athletic event of this nature,” said school security expert and former Dallas ISD Chief of Police Craig Miller.

Miller is not involved in the investigation but agreed to provide insight on school security.

He says it would also not be unusual for Frisco ISD to have a smaller presence of school resource officers on hand at competitions like Wednesday’s.

“When you hear about these cases, you’re struck with the tragic circumstances,” said defense attorney and former prosecutor Russell Wilson.

Wilson is also not involved in this case but agreed to give legal insight on the charge and potential impact of the location of the deadly encounter.

“The prosecution will be saying this is a place where you wouldn’t expect an incident like this to happen,” said Wilson. “I probably would expect the defense to say that they didn’t go to this incident or to this track meet intending for an altercation like this to happen.”

Whether words were exchanged may not matter, says Wilson.

“Texas law, though, doesn’t allow a person to use deadly force in response to verbal provocation alone,” he said.

It’s important to note, Wilson spoke with NBC 5 before the arrest warrant alleging the victim pushed the suspect was released.

Memorial High paused Thursday morning during second period to remember the 11th grader.

Metcalf’s accused killer is in jail. According to jail records, approved visitors include his parents, siblings and girlfriend.

NBC 5’s efforts to reach the suspect’s family for comment have been unsuccessful.