(NewsNation) —Jurors will hear from more witnesses as court continues Saturday in the murder trial for Texas teen Karmelo Anthony, accused in the fatal stabbing of fellow track athlete Austin Metcalf during a sports event last year. 

Judge John Roach Jr. ruled that the trial would resume over the weekend for its third day of testimony. 

On Friday, jurors were shown the pocket knife prosecutors say was used in the stabbing, along with photos of the weapon, Anthony’s backpack and the crime scene. 

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Opening statement set in Karmelo Anthony trial | Morning in America

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Opening statement set in Karmelo Anthony trial | Morning in America

An officer who responded to the scene after the stabbing had testified that a witness directed police to the knife, which was found in the bleachers. 

Jurors also watched body camera footage from the scene, and prosecutors demonstrated how quickly the knife could be opened.

Anthony was charged with first-degree murder after the alleged attack at a track meet in Frisco, a suburb of Dallas. 

Anthony says he stabbed Metcalf in order to defend himself from an imminent attack. 

Teen witnesses describe day of the attack 

On Friday, jurors heard from several teen witnesses who saw the incident unfold last year.

One witness, who was not named since he was 17 and was a fellow track athlete, told jurors he and Metcalf both asked Anthony to leave a team tent repeatedly on the day of the stabbing.

Anthony refused to leave and engaged in a prolonged verbal confrontation, he testified. The teen told jurors that no group of students ever “ganged up” on Anthony. 

The teen recalled Anthony telling Austin, “Touch me and find out,” and described both teenagers as angry, though he characterized Anthony as the one provoking the situation.

He said Austin eventually pushed Anthony, after which Anthony pulled a knife from his backpack and stabbed Austin in the chest. 

The teen told jurors that he and other students initially thought the knife was a “bluff” and did not expect Anthony to actually use it. 

The teen said he heard Metcalf say “Oh my God” before collapsing.

Opening statements present ‘sneak attack’ versus self-defense narrative 

Prosecutor Bill Wirskye told the jury Metcalf was killed in a “sneak, surprise attack” during the track meet, calling the act a “senseless murder” during opening statements.

“He didn’t want a fight,” Wirskye said of Metcalf, arguing that Anthony’s actions were not self-defense.

One of the most important pieces of evidence expected to be presented at trial is the surveillance footage from the stadium during the attack, which jurors watched during opening statements. Jurors viewed a grainy video of a tent in the bleachers and Anthony running away.

Prosecutors have submitted 35 witnesses they plan to call and are also expected to present the alleged weapon used in the attack. 

But defense attorney Mike Howard said Metcalf made the first contact. 

“In that split second, Melo has a decision to make: How and when to act. Self-defense is useless if you wait too late to defend yourself. … He reacts in a split second of fear, chaos,” Howard said during opening statements.