EXTENSIVE forensic tests on the body of murdered student Emer O'Loughlin are continuing this weekend. Gardaí hope that her killer may have left behind DNA still detectable five years after her death.

The body of the 23-year-old art student was discovered in a burnt-out caravan in Co Clare in April 2005. Her body was exhumed last week and a second post-mortem, due to advances in forensic science, confirmed that she was murdered. Until now, the cause of death had not been known but it was treated by gardaí as suspicious.

The decision to exhume the body was taken after a review of the investigation into her death by officers from the specialist cold case unit.

"The investigation is now at a critical point," said a senior source. "More forensic tests are ongoing at the moment. We are now hoping to find DNA left behind by her murderer on the body. Despite the fact that five years have passed, it is still possible that her killer left behind vital evidence. There have been dramatic developments in forensics."

O'Loughlin was living with her long-term boyfriend Shane Bowe at a small caravan park at Newline, Ballybornagh, between Kinvara and Tubber in Co Clare, at the time of her death.

They were living at the caravan site while they saved for a home together and the 23-year-old was considered a "free spirit". She was originally from Ennistymon and was a full-time art student at Galway-Mayo Institute of Technology. There were about five caravans at the site. Detectives want to speak to another man, who is in his 30s and was one of her neighbours at the caravan site, about her death.

After she was murdered, her caravan was set on fire. The damage to her body was so extensive that her sex could not immediately be determined.

Three days after her death, her neighbour began to act bizarrely. He travelled to the historic Dún Aengus ring fort on the Aran island of Inis Mór and threatened to throw himself from the 300-foot cliff there, hurling rocks at anyone who came near him. Gardaí in riot gear were flown in from the mainland and lifeboats bobbed in the water below in case the man carried out his threat. He was taken to a psychiatric hospital in Ballinasloe.

After five days in hospital, the man shaved off his distinctive dreadlocks and beard, which helped him escape detection, and discharged himself from hospital. He then returned to Dun Aengus and his clothing was found near the cliffs at the same spot. Despite extensive searches, gardaí have been unable to find him.

Detectives believe he was attempting to fake his own suicide and has now left the country. Gardaí say he is key to their enquiries and his details have been circulated with Interpol and Europol.

The young woman's family have welcomed the developments in the case and hope her killer will soon be brought to justice.