Influencer Liam Fitzgerald Fatal Motorcycle Crash: Heartbreaking 911 Audio

1:11 PM PT The cause of death has been determined to be blunt-force injuries, and the manner of death is classified as an accident according to the Broward County Medical Examiner.

The stranger who found Liam Fitzgerald after his motorcycle crash used the influencer's own phone to call 911 ... and the heartbreaking audio captures his desperate attempt to get help.

TMZ has obtained the call from the October 30 crash ... the caller tells a dispatcher he was driving home when he spotted a motorcycle in the grass in Miramar, Florida.

He pulled over to investigate and found Liam lying on the ground ... telling the dispatcher, "I'm glad I saw him."

As emergency crews rushed to the scene, the caller pleaded, "Please, please be quick."

The man also reported Liam appeared to have struck a traffic sign, which was bent ... though authorities have not confirmed what caused the crash.

In a particularly chilling moment, the caller reveals he's using Liam's own cellphone to contact 911 ... staying by his side until police arrive.

As TMZ previously reported ... dispatch audio revealed Liam was found motionless but apparently still breathing. Police told us no witnesses to the actual crash had come forward, and the investigation remained ongoing.