Student Kym Owens remains in an induced coma
Teenage law student Kym Owens, who last November was found seriously injured on a roadside in Maynooth, Co Kildare, remains in an induced coma in hospital - seven weeks later
Investigating gardai have not yet determined how she sustained her head injuries despite intensive inquiries.
Gardai officially described the incident as a serious assault when they launched their investigation.
But senior officers have not ruled out any possibilities.
Medical evidence indicated that she could have suffered the injuries to her eye sockets, jaw and teeth in a fall. But gardai say this does not explain why her shoes were found a short distance from where she lay.
One theory being investigated is that Kym might have been struck by a passing vehicle or trailer and then dragged along the ground as she walked to her student accommodation in the Moyglare Abbey estate.
She had earlier from her home town, near Castleblayney, on a private bus on November 20.
The area was shrouded in heavy fog at the time, and a driver might not have been aware of such an incident.