A TEENAGER who died unexpectedly in her sleep has been described as "our little angel" by her parents.

Mystery still surrounds the cause of death of Demi Sharif.

The 13-year-old, who had no known underlying health problems, was discovered in bed on Thursday morning by her mother Vicky Porrit.

The 29-year-old said: "She was our little angel and she didn't deserve this."

Her family, including father, Naeem Sharif, 41, brothers Ben, Lewis, Cameron, and sisters Bethany, Chloe and Jade, are now mourning the loss of the teenager.

A special assembly was held on Friday morning at the teenagers school, St Bede RC in Billingham, near Stockton, to mark her passing and to inform staff and students about the tragedy.

Social network sites were filled with moving tributes from friends with more than 3,000 people joining groups on Facebook.

A spokeswoman for Cleveland Police said: "Police were called to North Tees University Hospital at around 4.40am on Thursday, January 20 following the sudden death of a 13-year-old girl. Police are not treating the death as suspicious."