Senegalese migrant 'confesses' to American woman's murder

A 27-year-old Senegalese migrant has admitted killing 35-year-old American Ashley Olsen at her rented apartment in Florence, but claims it was an accident, prosecutors said on Thursday.

Cheik Tidian Diaw was arrested around midnight on suspicion of murder at an address in Florence, where has been living since arriving in Italy last year. Interrogated by police until 4am, Diaw told them Olsen had fallen and hit her head during an argument that broke out between them while they were having sex.

Florence's chief prosecutor Giuseppe Creazzo told journalists there was "very serious evidence" against Diaw, who was arrested on the basis of DNA evidence taken at the crime scene, including a condom and a cigarette butt found in Olsen's bathroom and skin lodged under her nails.

"Biological substances found on Olsen's body showed they had consensual sex," Creazzo stated.

Diaw was identified by witnesses who saw him leaving the Montecarla nightclub in central Florence with Olsen in the early hours of last Friday morning. Witnesses also saw him walking with Olsen back to her nearby apartment and the pair were filmed on security cameras outside the nightclub and in the surrounding streets, according to investigators.

"The murder took place sometime on Friday morning," Creazzo said. "Ashley's skull was fractured in two places," he stated.

Diaw claimed he pushed Olsen during their quarrel and that she had fallen and hit her head, but Creazzo said investigators believe the homicide was committed in two stages, first with a blow to the head and then via strangulation.

Olsen's naked body was found by her boyfriend Federico Fiorentini and her landlady on Saturday morning with bruises and scratch marks to her neck. An autopsy found she had been strangled with a chain or a computer cable and was killed sometime between 7am and 1pm last Friday.

Diaw had Olsen's mobile phone and had inserted his own SIM card in it, Creazzo told journalists. He was previously unknown to police and had been scraping a living in Florence distributing flyers for local nightclubs, Creazzo said.

"It doesn't appear that he and Olsen knew one another," Creazzo added.

"There is no evidence that an erotic game took place," Creazzo said, adding: "It's quite possible that they weren't in a lucid frame of mind."

Investigators were still awaiting the results of toxicology tests to determine if there were drugs or alcohol in Olsen's system when she was killed, he said.

Fiorentini provided police with an alibi on Monday and was not put under investigation.

Olsen, a divorcee from Florida was the daughter of an art historian and had been living for the past three years in Florence, where her father teaches.