Police are continuing to investigate the death of wrestling icon Hulk Hogan after a therapist present at the time of his passing raised concerns about a possible medical error, according to TMZ.

Hogan, born Terry Gene Bollea, was found unresponsive at his Clearwater home on July 24 following an apparent cardiac arrest. First responders were called after his wife, Sky, noticed he had stopped breathing.

An occupational therapist who was with Hogan reportedly told officers that the 70-year-old may have suffered a severed phrenic nerve during a recent surgery. The phrenic nerve controls the diaphragm, a crucial component in breathing.

The Clearwater Police Department confirmed Thursday that the case remains open. “The unique nature of this case has required us to interview multiple witnesses and seek medical records from a variety of providers, and our detectives continue to do that. All of this takes time,” the department said in a statement. Police also noted they have been in contact with Hogan’s children, Nick and Brooke, and said the family has been “appreciative of our efforts and our communication with them.”

Law enforcement sources told TMZ the investigation includes reviewing medical records and testimony from those who were present when Hogan’s condition deteriorated. Reports suggest Hogan did not appear to experience chest pain before his death, but suddenly stopped breathing.

The developments come shortly after Hogan’s daughter, Brooke, publicly called for the release of police body-camera footage from the day of his death.