The man accused of murdering and sexually assualting his step-granddaughter then hiding her body in the loft of his home repeatedly used his mobile to search for child porn, a court heard today.

Prosecutors say Stuart Hazell sexually assaulted and murdered his partner Christine Bicknell's 12-year-old granddaughter Tia Sharp at the couple's New Addington home.

In a letter sent to his father from HMP Belmarsh that was read out in court this morning the 37-year-old said Tia died in an accident and denied any of his actions were sexually motivated.

But this afternoon the Old Bailey heard Mr Hazell repeatedly accessed sites showing both adult and child pornography, in June and August last year.

Jurors were told a list of web addresses visited on Hazell's phone were analysed. Terms searched for through Google included 'schoolgirl nude', 'naked little girlies XXX.'

Junior prosecutor Jocelyn Ledward said: "Other search terms include 'naked little glasses XXX' and 'glasses very young XXX.' Mr Hazell sat in the dock with his head bowed as various search terms were read out.

The court also heard about recovered images on a memory card found on a hallway cupboard. Some photos showed images of child and adult pornography and the card also held three clips of Tia sleeping on it.

Earlier this afternoon forensic scientist Frederic Boll told the court he found two possible areas of semen staining on the floor of Tia's room, one had no DNA profile, the second matched Mr Hazell's DNA.

He said he also had to search the house for signs of blood staining.

A blood stain was found on a mattress and on the loft hatch in the property, but neither had a DNA profile.

Asked by the defence about blood stains on an umbro t-shirt he was asked to examine, Mr Boll confirmed white paint was clearly on top of the blood stains.

He told jurors he couldn't say from his examination when either the blood or the paint got on to the t-shirt.

Mr Hazell denies murder. The trial was adjourned until 10.15am on Monday.