Police are investigating why a wire which caused a fatal accident had been suspended between two trees across a dirt track in Lancashire.
Ryan Acaster, 17, from Brinscall, near Chorley, was thrown from his motorcycle after hitting the wire on a track off New Lane in Crossens, Southport.
Lancashire police's major investigation team is looking into Sunday's incident and is appealing for witnesses.
Tests have revealed that Ryan died from head injuries.
He was flown by air ambulance to the Royal Preston Hospital after being found injured, but died later.
A police spokesman said: "There is no indication at this time that this situation arises out of a deliberate attempt to cause harm although the circumstances will now be investigated in order to establish the full facts."