A 22-year-old man aboard a Southwest Airlines flight from Dallas to Los Angeles died after suffering from a medical emergency mid-flight, according to a report.

Southwest Flight 958 was in the air traveling from Dallas Love Field Airport to Los Angeles International Airport Friday morning when a passenger went into medical distress and became unresponsive, law enforcement sources told NBC4.

The man, who was identified by the Los Angeles County medical examiner’s office as 22-year-old Rain McMillan Walmsey, received CPR from someone on the plane while it was still in the air.

The plane was met by paramedics when it touched down in Los Angeles. However, the first responders were unable to revive Walmsey.

Firefighters pronounced him dead at the scene, the source told the outlet.

It was not immediately clear what type of medical emergency the 22-year-old suffered from.

While the medical examiner confirmed Walmsey’s identity, the cause of his death remains under investigation.

Southwest confirmed in a statement that a “medical incident involving a customer” occurred on the flight Friday morning, but did not provide any additional details.

The Independent has contacted Southwest for more information.