Fibres from a single glove linked farm labourer John William Cooper to four murders, a rape and a robbery, a jury heard today.

The glove was found by PC Mark Jenkins in November 1996 as he responded to a brutal robbery at the home of retired teacher Sheila Clark.

PC Jenkins followed a route across farm land near her home in Sardis.

He found a sawn off shotgun, Mrs Clark's stolen handbag, a Balaclava and a glove - and the trail led to the door of Cooper's home.

Twenty one years later, during a cold case review, experts were able to find fibres from the glove on shorts belonging to murder victim Gwenda Dixon.

The shorts - which Cooper went on to wear as if they were his - revealed the DNA of another murder victim, millionaire farmer Richard Thomas.

Fibre transfer also connected the glove to the rape of a 16 year old-girl in what were otherwise completely unconnected crimes, said Gerard Elias QC, at Swansea crown court.

Cooper, now aged 66, of Spring Gardens, Letterston, denies murdering Richard Thomas, 58, and his sister Helen, 56, at their home at Scoveston Park on December 22, 1985.

He also denies murdering marketing director Peter Dixon, 51, and his wife Gwenda, on June 29, 1989.

Cooper also denies raping the teenager, indecently assaulting another and trying to rob three more.

Cooper was convicted of the Sardis robbery, plus 30 burglaries, in December 1998 and jailed for 16 years.

But police were unable at the time to link him with the crimes for which he is now on trial.

Mr Elias has told the jury that Cooper "mercilessly executed" four people in return for pitifully small amounts of money.

Cooper blasted them to death with a shotgun just to ensure his escape, he said.

And he probably decided not to shoot a group of teenagers he had attacked only because there were too many of them, he alleged.

But before leaving them "cowed and terrified" he fired the gun in the air and warned them he would murder them if they went to the police.

Mr Elias told the jury today (Wednesday) how advanced scientific techniques could now link items found during the 1998 inquiry with more crimes.

The glove, he said, was examined by expert Roger Robson, who had 20 years experience of forensic science. He would tell the jury that he also examined a pair of green, tie up shorts found in the bedroom of Cooper's home.

Cooper's DNA was found on a handkerchief in a pocket. Also found was the DNA of the Dixons' daughter. Julie, and the shorts must have been taken from the point on the Pembrokeshire Coastal Footpath where the Dixons had been shot dead.

He also found fibres from the glove from the Sardis trail, which were also on clothing worn by the girls sexually assaulted in a field.

Other fibres on the shorts came from a sock worn by Richard Thomas.

Fibres from the glove were also found on a box of shotgun cartridges found buried in a duck run at Cooper's home.

"Are these things merely unhappy chances or co-incidence? Without a shadow of doubt it was the defendant who had been wearing that glove.

"It is obvious from any objective analysis that these offences were committed by a local man and the evidence is plain - that local man was the defendant," added Mr Elias.

Cooper served 10 years in jail for the robbery and burglaries. While he was inside a cold case review began to connect him to the crimes he is now accused of, it was alleged.

The killings, said Mr Elias, involved "the use of cold, calulating violence and the merciless execution of four people for pitifully small financial gain but to ensure their silence."

"It might be the teenagers were spared because there were too many of them to be executed.

The first witness in the 10 week trial will be called tomorrow (Thursday).