Wiltshire Police are still appealing for witnesses following the discovery of a body on the A3012 at Royal Wootton Bassett on Sunday.
They're investigating the death as a hit and run.
The woman had received extensive head injuries and was pronounced dead at the scene.
Police are keen to trace any vehicle(s) that were driven from the direction of Junction 16 of the M4 towards Royal Wootton Bassett that may have struck the victim on the road.
– Police sergeant Craig Hardy
Witnesses have described seeing large goods vehicle parked in a lay-by close to the site of this incident and we are urging the driver of this vehicle to contact Wiltshire Police as they may hold valuable information to assist with our enquiries