The body of Ian Pullen was discovered on the side of the road early on September 29, 2018, at Glenridding near Singleton.
NSW Police arrested a 21-year-old woman on Monday morning at a home in Whittingham.
She has been charged with being an accessory after the fact to murder, and was refused bail to appear at Muswellbrook Local Court on Monday.
Two other people - a 30-year-old woman and 29-year-old man - were charged with murder earlier this year and are before the courts.
Police will allege the man was driving a white Toyota Hilux utility when the 43-year-old Mr Pullen was hit.
Police say the car returned a short time later and the man and woman struck Mr Pullen in the head with an object.
The Daily Telegraph reported that police will allege that the woman arrested today was in the car with the other two when the vehicle hit Pullen.
