Forensic examinations of the blade found close to the body of 17-year-old Stephen Lyne in Killarney are expected back early next week and detectives are hopeful it will lead them to the killer of the young student.

Garda sources confirmed that Stephen's mobile phone has also been found and is being examined. "We have located a number of items, including a blade, that are being forensically examined. It was found close to the body but has not been identified formally yet as the murder weapon," according to a source.

Gardaí involved in the murder investigation held a case conference yesterday.

House-to-house enquiries were continuing this weekend and in excess of 30 people who may have been in contact with the teenager have been interviewed.

"There is no suggestion yet that a culprit has em­erged. It is more than likely a local. We're trying to establish exactly where he was that night and what he was doing. We do believe he walked home alone," according to another source.

Gardaí believe whoever attacked Lyne may have been attempting to mug him. "The lining of his pockets had been turned out so that's what it looks like," said the garda.

Officers are still studying CCTV and trying to establish if the teenager had been involved in a row with anyone last Wednesday night in the hours before his body was discovered.

Stephen, known locally as Stefan, died after he was stabbed in the back on Ross Road in Killarney as he made his way home to the Castle Falls estate in the Kerry town in the early hours of Thursday morning.

"That he was taken from us in such a mindless violent manner, if possible, only adds to the agony," his parents, Denis and Lotte Lyne, said in a statement.

Gardaí are continuing their search of the area around the murder scene where they located the knife and the area where they recovered the victim's mobile phone in a field behind the murder scene. The fifth-year student at Killarney Community College was seen with numerous friends and young people in Killarney town centre in the hours before his death.

Meanwhile, gardaí are continuing their murder investigation into killing of drug dealer 20-year-old Tommy Joyce. He was shot in the head and chest outside his home on the Grove Lane halting site near Darndale, north Dublin on Wednesday night.

They believe he may have been killed because a machine pistol he was rumoured to own was the same model of weapon used to kill drug dealer BJ Clarke (21) in north Dublin in April.