Police hope to definitively wrap up their investigation into the November murder here of a 22-year-old British exchange student by the end of the summer.
Assistant prosecutor Giuliano Mignini said that while no exact timetable has been set, he was confident the probe would be completed this summer.
Meredith Kercher, 22, was found November 2 with her throat slashed in the house she shared in Perugia with three other girls.
Three people are currently in custody in connection with her murder: Kercher's 20-year-old American roommate Amanda Marie Knox; the roommate's 24-year old Italian boyfriend Raffaele Sollecito; and 21-year-old Ivory Coast national Rudy Hermann Guede.
Although investigators admit they remain in the dark in regards to the motive, they claim the forensic evidence they have gathered so far against the three suspects is rock solid.
On Thursday, investigators confirmed that they had found Sollecito's DNA on the victim's bra and that this had definitively placed him at the scene of the crime.
Sollecito's father, however, disputes this conclusion and said his son was not in the room where Kercher was murdered and that his DNA was on the bra probably because Knox borrowed it.
''Amanda had a habit of borrowing other people things, including my son's boxer shorts. I don't think she would have thought twice about using her roommate's clothes,'' Francesco Sollecito said.
Lawyers for Raffaele Sollecito said their client was ''surprised'' his DNA had been found on Kercher's clothing.
The DNA was found on a small piece of cloth cut by a knife close to the bra's fastener.
Recent forensic tests have also identified Guede's DNA on the victim's purse, which had been on her bed, as well as on the cuff of her running suit.
Guede's DNA had already been found in the toilet at the murder scene and in a vaginal swab of the victim.
He also left a bloody fingerprint of Kercher's pillow.
Guede, as opposed to Knox and Sollecito, has admitted being at the scene of the crime but denies any involvement.
Other forensic evidence includes a large kitchen knife found in Sollecito's kitchen which had the victim's DNA on the blade and Knox's DNA on the handle.
DNA belonging to both Knox and Kercher were also identified in a drop of blood found in the victim's bathroom.
Police also have a footprint left in Kercher's blood which matched the size and make of sneakers owned by Sollecito.
However, no traces of blood have been found on his sneakers.
In an 18-page preliminary report made public last month, police said their investigation and the evidence gathered ''proved a direct relationship between the suspects and the victim and the presence of the suspects in the apartment at the time of the attack on Meredith''.
Guede claims he was in the bathroom at the time of the murder and that when he came out he saw the murderer, who tried to attack him.
Although this hypothesis has not been ruled out, a preliminary hearings judge who denied him bail last month found his testimony to be ''contradictory, incomplete, unlikely and illogical''.
Similar arguments were used to deny bail to Knox and Sollecito at the end of November.
