A 17-year-old boy has been arrested in relation to the case and faces charges of homicide and desecration and concealment of a body.
The boy, who is being held in pre-trial detention at the Casal del Marmo juvenile prison in the capital, is alleged to have killed Causo with at least six stab wounds to the neck, abdomen and back in the apartment where he lived in Primavalle.
Investigators are working to establish the motive for the attack.
The autopsy results suggest that the victim tried to defend herself.
The brutality of the attack, the age of the victim and the suspect, and the way the body was treated have caused widespread shock and dismay in Italy.
“What happened tells us about a broken world, a world that burns youth, that chases illusions, that does not know how precious a life is,” Bishop Baldo Reina said in the funeral homily.
“Our pain must now become a denunciation, it must translate into change.
“The fruit of this death must not be wasted.
“It must become a sign of the need to change this world of ours together.”
ANSA