A convicted double murderer was tonight found guilty of having committed a third murder in Cospicua in 1986.

Saviour Mangion, who has already been condemned to a life sentence and a 21-jail term for his previous murders, was unanimously convicted by a jury of the 1986 fatal stabbing of Maria Stella Magrin, 68, in her home.

Prosecutor Nadine Sant called for a life sentence, saying it was extremely rare to have a unanimous guilty verdict after a trial by jury.

Sentence will be handed down in Monday.

The elderly woman was stabbed 13 times during a robbery.

The Zejtun man was last July found to be mentally fit to stand trial.

His lawyer had submitted that he suffered schizophrenia for at least 16 years, and it was likely that he had mental health problems well before that.

However the prosecution said that the accused was lucid when he admitted to the crime to the police in 2005. He had gone into minute detail about how the crime was carried out.

Mangion is in prison serving a life sentence for the murder of Rosina Zammit, 54 in Safi in 1984. He was also jailed for 21 years for the murder in 1998 of Francis Caruana. He stabbed both repeatedly.

Magrin was fatally stabbed in a robbery involving three men. According to court testimony, Mangion knocked on the door and the victim opened without asking who it was. The three forced their way upstairs, robbed her and killed her.

Mr Mangion had been described as Malta's serial killer by Mr Justice Joseph Galea Debono after his second conviction.cond conviction.