Italian police searching for the killer of the British exchange student Meredith Kercher are scouring her diary for clues.

They said that it contained telephone numbers, names, appointments and “thoughts on her life and friends”, although there were no entries for the day of her fatal appointment on November 1 with whoever killed her.

There is speculation that two men may have been involved, with one holding the woman down while the other killed her. One theory is that Ms Kercher, from Coulsdon, South London, met the man, or men, for sex last Thursday night but that the encounter turned nasty.

Italian media reports yesterday claimed that Ms Kercher, 21, had been “sexually violated” and had put up a struggle. Bruises and cuts suggested that her killer had gripped her throat with his right hand while using a penknife or Swiss Army knife to cut her throat with his left hand. Responding to the reports, Luca Lalli, the pathologist in the case, insisted that she had not been raped, although he said that there were bruises and lesions on her body consistent with a struggle.

The door to her bedroom in the cottage where her body was found was locked from the inside. The killer left by a window. Neither the key nor the murder weapon has been found.

Ms Kercher’s family issued a statement yesterday, calling on anyone with information to come forward. It read: “Meredith was one of the most beautiful, intelligent, witty and caring people you could wish to meet. Nothing was ever too much effort for her — a loving daughter and sister and a loyal friend.

“A genuinely caring person, she would check in with one of us almost daily just to chat and see if we were OK. She was looking forward to returning home this weekend for her mother’s birthday, with her suitcase laden with chocolates.”

Police are trying to determine the sequence of events on the night of the murder. Sophie Purton, a friend, said that she and Ms Kercher had watched a film together before Ms Kercher left her house at 9pm, saying that she was tired after a Hallowe’en party the night before and was going to bed. However, forensic scientists have pinpointed the time of death as 2am. “We want to know what happened in those five hours,” a police source said.

Police believe that Ms Kercher knew her killer well enough to open the door to him. It emerged yesterday that traces of blood had been found not only in the cottage, which she shared with three housemates, but also in another cottage on the hillside below them, rented by four Italian students from the Le Marche region. Reports said that the killer appeared to have cleaned himself up after the bloody murder not only at Ms Kercher’s house but also in the one below, to which he evidently had a key, since there was no sign of a break-in.

The four students from Le Marche were not in the house at the time. All have alibis, police said.

The atmosphere in Perugia remains tense. Some students who, like Ms Kercher, were seconded to the Perugia University for Foreigners from the Italian course at the University of Leeds, said that they were going back to Britain for a break. Some said that they may not return. Bar owners paid for a torchlit mourning procession to tour the town with a giant portrait of the dead girl.

One theory is that Ms Kercher met her killer at the Hallowe’en party at a city pub. Media attention has focused on North African men who attended.

On Sunday evening her housemates — two Italians and an American — were taken back to the cottage. Dr Lalli said this was because of “interesting elements” in his post-mortem examination, but would not elaborate.

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