The FBI and cops are investigating the spread of fake social media posts about the death of Frisco, Texas, high school football star Austin Metcalf, who authorities say was stabbed by a teen from a rival school at a track meet.

The 17-year-old athlete and honor student died after he was knifed in the chest allegedly by Karmelo Anthony, also 17, following an altercation. Metcalf’s family said he had never met the other teen before and that the confrontation turned violent within seconds when Anthony pulled out a knife.

In the wake of the slaying, a spate of bogus accounts impersonating the local police chief and medical examiner’s office have popped up, spreading falsehoods about his demise — including one fake viral post claiming Metcalf actually died from a drug overdose.

Another fake post, which impersonated the Frisco police chief, claimed that Metcalf was killed after beating Anthony repeatedly during “mutual combat.”

Austin Metcalf, a 17-year-old athlete and honor student, died after he was knifed in the chest allegedly by Karmelo Anthony, also 17, following an altercation at a track meet in Frisco last Wednesday, cops said. Family Handout

One doctored image that claimed to be a report from the Collin County Medical Examiner’s Office falsely stated Metcalf’s primary cause of death was an “MDMA drug overdose” — and that the stab wound was secondary, police said.

“The Frisco Police Department is aware of an image circulating on social media purporting to be a report from the Collin County Medical Examiner’s Office. At this time, the report has NOT been released. Therefore, any information currently found online is FALSE,” the department said in an X post.

Meanwhile, a fake social media account was also set up impersonating Frisco Police Chief David Shilson — drawing a criminal investigation by the FBI and Frisco police, according to WFAA-TV.

The fabricated statement quoted the police chief as saying Metcalf had “sucker punched” his alleged killer first and that he’d also “smashed [Anthony]’s phone onto one of the bleachers” — leading to a “mutual combat altercation.”

Karmelo Anthony, also 17, has been charged with first-degree murder. Collin County

“Beware of those taking to social media to deliberately spread misinformation, hate, fear and division,” Shilson said in a statement.

“I ask everyone to be cautious of the inaccurate information that is circulating related to this incident, and to only trust information that comes from official releases and verified sources.”

Even Anthony’s family has disavowed that fake account. In a statement, the family said a GoFundMe that was raising money off the claims was a fraud.

The conspiracy theories about Metcalf’s death started spreading after Anthony, who told cops he was acting in self-defense, was taken into custody and charged with murder last week.

The bloody ordeal unfolded after Metcalf, a Memorial High School junior, had asked Anthony to move from underneath his school’s pop-up tent during a rain delay at the meet, according to an arrest report.

Anthony, who went to nearby Centennial High School, immediately unzipped a bag, reached inside and told Metcalf, “touch me and see what happens,” a witness told police.

Moments later, Metcalf “grabbed Anthony to tell him to move and Anthony pulled out … a black knife and stabbed Austin once in the chest,” cops said.

Metcalf died in his twin brother Hunter’s arms.

Austin died in his twin brother’s arms. x/AMetcal

“I put my hand on [his chest], tried to make [the bleeding] stop, and I grabbed his head and I looked in his eyes. I just saw his soul leave. And it took my soul, too,” Hunter told Fox News in an emotional interview the next day.

The teen suspect fled but was quickly arrested, police said.

“I was protecting myself,” Anthony allegedly told cops as he was nabbed. “He put his hands on me.”

Anthony’s dad later told The Post that the teen was provoked.

He is being held on a $1 million bond.