Raffaele Sollecito has been in prison since November
A Japanese comic featuring vampires inspired a suspect in the murder of British student Meredith Kercher in 2007, an Italian prosecutor has said.
But the theory was described as "stupid" by the lawyer representing the suspect, Raffaele Sollecito.
An Italian court heard this week that Miss Kercher had 43 separate wounds.
Rudy Guede, 22, from Ivory Coast, American Amanda Knox, 21, and her Italian boyfriend Mr Sollecito, 24, deny sexual assault and murder.
Miss Kercher, 21, from Coulsdon, south London, was found semi-naked with her throat slit in her flat in Perugia, central Italy.
She lived with Miss Knox and others at the apartment on Via Della Pergola just outside the city's walls.
A series of pre-trial hearings are expected to finish on Tuesday, when judge Paolo Micheli will decide whether Mr Sollecito and Miss Knox will stand trial for murder.
As provided for under Italian law, Mr Guede has opted for a special fast-track trial which will allow him some leniency if convicted. Prosecutors have asked for a life sentence for Mr Guede.
Prosecutor Giuliano Mignini claimed a "manga" magazine, featuring vampires and found in Mr Sollecito's house, inspired the murder.
Manga comics are often associated with science fiction and fantasy, commonly with violent or explicitly sexual content.
Mr Sollecito's defence process is due to begin on Friday.
Francesco Maresca, the Kercher family's lawyer, has said Miss Knox was named as prime suspect because Meredith's body had been covered by a duvet - thought to be the act of a woman.
But Miss Knox's lawyers have argued there is no proof she was involved in the murder and there are no grounds for putting her on trial.
On Monday, it was announced the Kercher family was seeking £19m in compensation for Meredith's death as part of the Italian civil law process.
Miss Knox and Mr Sollecito have been in jail since November, while Mr Guede was arrested later in Germany and extradited to Italy in December.