Two teenage girls aged 13 and 14, took selfies and posted them on Snapchat while they battered a woman to death with a television set, computer printer, a kettle and knife.
The case was opened in a court hearing which held on wednesday, July 1st.
Angela Wrightson, 39, was subjected to a 'sustained and brutal' assault before her half-naked body was found at her home in Hartlepool, in December 2014.
Two teenage girls, who were aged 13 and 14 at the time of the killing, are accused of carrying out the attack, while the younger girl is said to have published a selfie taken at Ms Wrightson's home after the violence began on social media app Snapchat.
Ms Wrightson and the other girl, her best friend, could be seen in the picture and the older woman already had marks on her face, the court heard.
Both girls were grinning, but Ms Wrightson was not.
The jury had heard how Ms Wrightson, an alcoholic who would buy cigarettes and drink for underage youths, was found dead by her landlord.
'The body was sitting on a sofa in her front room, she was naked from the waist down,'Mr Campbell said.
The landlord dialled 999, and emergency services were called to the property. Forensic experts found shards of glass and gravel around the victim's 'private parts', and ash in her right ear.
Mr Campbell said: 'It became clear that Angela Wrightson had been the victim of a sustained and brutal assault.