A FORMER North-East student described by police as a "serial killer in the making" was jailed for life last night for murdering a teenager and dismembering his body.

Ex-Teesside Polytechnic student William Beggs, 38, was found guilty at the High Court in Edinburgh of killing Barry Wallace, 18, after sexually assaulting him.

The victim's head was found washed up on a beach near Troon and his limbs were discovered 60 miles away in Loch Lomond.

The court heard how Beggs, now living in Kilmarnock, picked up Mr Wallace in 1999, and took him back to his flat where he murdered him before dismembering his body.

Last night, it emerged that Beggs had previously been jailed for life for the murder of barman Barry Oldham after he picked him up in Newcastle gay club Rockshots - but he was freed to kill again after only 18 months.

Beggs, originally from Northern Ireland, was jailed in 1987 at Teesside Crown Court for killing Mr Oldham.

The 28-year-old was found dumped on the North York Moors with his throat slashed. Beggs claimed he had acted in self-defence when Mr Oldham made homosexual advances. Prosecutors maintained he was killed at Beggs' Middlesbrough flat.

But the conviction was overturned by the Court of Appeal because the original jury had wrongly been allowed to hear evidence of other razor attacks by Beggs.

Yesterday, trial judge Lord Osborne said: "Having regard to the circumstances of the case, in particular the seriousness of the appalling offences involved and having regard to your previous convictions, the part of your sentence which must be specified is 20 years."

Beggs was also placed on the sex offenders' register after the jury ruled that he had sexually assaulted Mr Wallace after handcuffing him by the arms and legs.

Last night, the man who led the inquiry into Beggs's first murder case said that, at the time, he had no doubt he was capable of killing someone else.

Retired detective chief superintendent Tony Fitzgerald, the former head of North Yorkshire CID, said: "When we caught Beggs all those years ago, we seriously thought we had caught a serial killer in the making. We thought we were lucky because we had managed to catch him after his first killing.

"When his conviction was overturned on appeal, I remember I was quite aghast at what had happened in the light of what we knew about this man."

The court in Edinburgh heard how Beggs lured Mr Wallace back to his flat and sexually assaulted him. It is thought he died during, or soon after, the assault

Beggs cut up Mr Wallace's body on the floor, put the limbs in bin liners and dropped them into Loch Lomond. It is believed he threw the head from a ferry.