Emotional moment in Karmelo Anthony‘s murder trial … tears started flowing as prosecutors played bodycam footage of paramedics trying to save Austin Metcalf from a fatal stab wound.

The gut-wrenching footage played in court Friday, showed paramedics giving Austin CPR after he was stabbed at a Texas high school track meet. He’s unresponsive on the ground as they try to save his life.

It was hard for Austin’s parents to watch … they broke down in tears and were held by family members while the footage played.

Prosecutors showed the intense scene after Frisco Police Officer Jacob Shalz — the cop who found the alleged murder weapon — took the stand.

Shalz testified he found the knife in the bleachers, “approximately three to four rows up above the crime scene.” The prosecution showed a picture of the bloody knife, which reportedly looks like a 5-inch folding knife.

He also told the court he found Karmelo’s backpack and covered it to protect any evidence from the rain. The backpack and the knife were both entered into evidence.

As you know, Karmelo’s charged with murder for allegedly stabbing Austin to death … he’s pleaded not guilty. The trial got underway this week and if convicted, he could face life in prison.