A HOMELESS man who had been out of jail for just five days bragged to friends that he had killed a man, a jury has heard.

Gareth Wyn Jones launched a brutal and savage attack on David Alun Lewis under a secluded river bridge, Cardiff Crown Court was told.

The 45-year-old's body was found partially submerged in the River Taff in the Welsh capital. He had suffered more than 80 blunt force head injuries and had been strangled.

Jones was later found with Mr Lewis's bank card and also tried to buy heroin with blood-stained money.

The 28-year-old has admitted manslaughter, but denies murder on the grounds of diminished responsibility.

But in his closing speech, prosecution counsel Vincent Coughlin QC described the defendant as manipulative and making up symptoms to "suit his own ends".

He said: "This was a calculated and premeditated killing done for gain.

"The defendant identified David Lewis as easy prey when he first met him.

"He attached himself to a vulnerable man with the intention of finding out what he had that he could take from him.

"He was heard then bragging about the killing ... as if it were a badge of honour to people he thought would have no intention of going to the police.

"In the course of these admissions he acknowledged he had left Mr Lewis for dead face down in the river."

Musician Mr Lewis, originally from Ystrad Mynach in Caerphilly, has been described as "vulnerable, fairly quiet and a bit of a loner".

The court has heard he spent the greater part of his life fighting anxiety, depression and alcohol and would stay in hostels in Cardiff from time to time.

Mr Lewis's battered body was found underneath the Taff Embankment Bridge late on March 19.

He met Mr Jones at a hostel in Cardiff just 90 minutes earlier.

Prosecution counsel Mr Coughlin said after the killing the defendant walked away as if "nothing had happened".

Two attempts to withdraw money from Mr Lewis account were made a few hours later.

"How did the defendant get the pin number after he had stolen the card?," Mr Coughlin asked the jury.

"A more sinister explanation - he extracted the number in the course of the killing on the Taff Embankment.

"The deceased received 80 blunt force injuries to the head, 20 to the neck as well as other injuries "These were a sustained series of assaults ... not a single a fatal blow.

"It must have taken some time for all these injuries to be inflicted.

"Perhaps it could be in the course of this grim sequence of events he extracted the pin number."

Mr Coughlin said the fact the card was used either side of midnight was significant, suggesting the defendant had done so to see if Mr Lewis' benefits had been paid in - a fact the Crown highlighted as Jones being in control of his actions.

Following the killing, the court heard Jones had thrown away his bloodstained clothing before "feigning" illness and was taken to hospital.

"He agreed to suffering every single symptom that was put to him," added Mr Coughlin. "If he would have been asked had he lost a limb he probably would have said yes to that as well."

After his arrest on March 20, Mr Coughlin said Jones kept changing his story - first claiming insanity, self defence and provocation before launching a defence of diminished responsibility.

A jury has been previously told Jones was released from a prison on March 14, after serving half of a six-year prison term.

And it has also learned the defendant has been diagnosed with a severe borderline personality disorder.

But the Crown has highlighted expert evidence from psychiatrists pointing out that Jones has shown no symptoms of suffering from a psychotic mental illness - such as schizophrenia.

Mr Coughlin reminded the jury of consultant forensic psychiatrist Philip Joseph's evidence - saying it was unlikely the defendant had ever suffered "true auditory hallucinations".

He also said mental health nurses at Ashworth Psychiatric Hospital in Liverpool, where Jones is currently under care, expressed their doubts about his "psychotic episodes".

Dr Joseph said: "Whether it (the killing) was done premeditated or impulsively it does not substantially impair his ability to form a rational judgement.

"It is my opinion...he was not suffering from any mental illness - for example paranoid schizophrenia - at the time."

In his final address to the jury, Mr Coughlin said: "Do not let the fact that the defendant was troubled and had a traumatic childhood distract you.

"We have heard nothing about the details of Mr Lewis' life. We are not asking for sympathy either.

"We are simply asking that you try this case and give a true verdict according to the evidence."