What killed Jayden? Mystery surrounds man found on Central Coast road

Police are investigating the mysterious circumstances surrounding the death of a 21-year-old man who was found badly injured and unconscious on the NSW Central Coast.

Jayden Mason was lying on the road with severe head injuries when a passing motorist spotted him in Lake Haven about 10.30pm on Saturday.

He was treated at the scene by paramedics and taken to John Hunter Hospital.

Police aren't sure exactly what happened to Jayden Mason. Source: 7 News

On Sunday, his family made the heart-rending decision to switch off his life support after they discovered the extent of his brain damage.

Police say they are investigating "all lines of inquiry" into what caused the death, including whether Jayden was bashed or hit by a car.

Seven News has been told Jayden was kicked out of Wyong Rugby League Club and was involved in a fight outside.

Jayden suffered critical injuries and has since died in hospital. Source: 7 News

The young man's family is struggling to come to terms with the tragic death.

Jayden's friends paid tribute to him as "one of the greatest people" they knew.

The site where Mr Mason was found with serious injuries. Source: 7 News

"I love you forever Maso, thank you for all the memories growing up," a friend wrote on Facebook.

"You will never be forgotten. You will live forever in our hearts."

Jayden was just 21-years-old. Source: 7 News

Police are appealing for information, and would like to speak with a woman who stopped to help the injured 21-year-old.

She is described as being in her 50s, and was driving a dark blue Ford Falcon sedan towing a box trailer.