A convicted murderer serving a life sentence kept a cup of human excrement and a container of sperm in his cell to throw at prison warders, a court heard yesterday.

The disgusting details emerged yesterday as 35-year-old David Schembri was charged with setting fire to his cell on April 11, at about 5.10 p.m. and threatening prison warders. He is pleading not guilty.

He was jailed for life in 2009 for stabbing to death the mother of his child, Josette Grech, 32, some 47 times in May 2004. His daughter, then aged seven, witnessed the first part of the attack before she was taken away by a neighbour. Police Inspector Spiridione Zammit said yesterday that he had received a phone call about the prison incident informing him that inmate 69676 in cell number 17 within division 6 had set fire to his cell.

The mattress was completely burnt and the walls were black and Mr Schembri was transferred to a new cell. The damage amounted to €226. When he questioned Mr Schembri about the incident, he was at first very sarcastic and then refused to answer any questions before standing up and becoming very violent. In fact, he had to be escorted away by Special Response Team personnel, stationed at the prison.

Police Sergeant Justine Grech said that officers who had carried out routine inspections in his cell had found a cup containing human excrement and when asked for an explanation, Mr Schembri said he wanted to throw it in the face of a warder.

In another similar incident, officers found a plastic bag which had a strange smell. Inside was a container and when they questioned him about this, he told them it was sperm that he was saving to mix with acid so he could also throw in the face of a warder, said.

The officer testified that prison warders Godwin Agius and David Abela reported that they had been threatened by Mr Schembri.

Testifying, Mr Agius said that they were ordered to transfer the inmate to a new cell and to carry out a strip search for his own safety. It was during this strip search that he was threatened.

He told Mr Schembri to take his shorts off so that he could remove the draw string, for his own safety, but the shorts tore a little as he tugged at the string. Mr Schembri told him that they had a score to settle over this, insinuating that the officer had torn the shorts on purpose. Mr Schembri added that he had not forgotten that Mr Agius had also taken his shoes during a previous inspection sometime before the fire.

Mr Agius said that he took the shoes because a hole was found in one of them where a mobile phone could be hidden.

Mr Schembri’s criminal record has no fewer than 12 convictions for driving offences, possession of cannabis, heroin and cocaine and trafficking drugs.

Mr Schembri was back in court in June 2010 for allegedly slashing another inmate in the face with a makeshift knife. The case is still pending.