A Senegalese illegal immigrant has been convicted of murdering an American woman in her apartment in Florence, Italy after they met at a nightclub.

Cheik Tidiane Diaw, 27, has been jailed for 30 years for murdering Ashley Olsen, 35, in her apartment on January 9 this year after they had sex.

Olsen, from Summer Haven, Florida, was strangled and suffered several skull fractures. Her body was found by her boyfriend.

Diaw, who had arrived in Italy from Senegal a few months earlier, admitted to police he and Olsen fought violently after a night of drugs and sex but denied strangling her and said he never intended to kill her.

Cheik Tidiane Diaw (pictured, left) has been jailed for 30 years for murdering Ashley Olsen (right) in Florence in January this year

Diaw told investigators they had fought when she tried to push him out of the apartment, fearing her boyfriend would be arriving.

After being pushed against the door, Diaw responded by punching Olsen in the neck and then pushing her to the ground, where she hit her head.

Police arrested Diaw after street surveillance cameras showed him walking with Olsen toward her home that night.

His DNA was found on a cigarette butt and a condom in her apartment.

Ashley Olsen's mother Paula (left) was on the verge of tears as the verdict was read out

Diaw claimed he killed Ashley (right) when she tried to kick him out of her apartment after they had sex because she feared her boyfriend Federico Fiorentini (left) was about to return

Prosecutors, who accepted the pair had consensual sex, had sought the maximum sentence of life in prison.

Ashley had moved to Florence a few years ago and was active in the expatriate arts scene. Her father Walter is a professor at a local design institute.

Just after her death, friends described Ashley as a vivacious and fun-loving character while her father voiced his heartbreak at losing 'a beautiful and creative young woman with a happy, exuberant and generous soul, who loved her life in Florence'.

Ashley (pictured) was described as a 'happy, exuberant and generous soul' by her father

A photograph of Ashley Olsen was placed on a table as the verdict came in

Diaw holds his head in his hand after the verdict was read out. He faces 30 years in jail

Walter Olsen and his ex-wife Paula issued a statement in February saying: 'If it is true, as the authorities declared during a press conference, that Ashley was under the influence of alcohol or other substances, then any type of sexual activity that she might have had that night was not consensual.

'She was not the kind of girl who would have consented, willingly,' they said.

But the prosecutors accepted the pair had consensual sex.

Ashley (pictured) was often to be seen strolling around Florence with her pet beagle (pictured)

Mourners at her funeral in Florence's Santo Spirito basilica in January were shocked when an Italian bishop, Monsignor Giovanni Scanavino, said blamed her friends for not being 'sufficiently human and Christian' and failing to prevent her getting involved involved in the 'deadly tangle of alcohol and drugs'.

Diaw, who plans to appeal, had arrived in Italy illegally and told investigators he was working odd jobs, handing out flyers for local nightclubs.

The case attracted considerable international media attention and investigators were keen to avoid any repeat of the drawn-out saga that followed the 2007 killing of British student Meredith Kercher in Perugia, not far from Florence.

Kercher's American flatmate Amanda Knox and her Italian boyfriend spent almost four years in prison for the crime before finally being acquitted last year by Italy's highest appeals court.

Paula Olsen is comforted by her lawyer Michele Capecchi after the verdict

Ashley Olsen's family originally claimed she must have been raped by Diaw but the prosecution accepted the pair had consensual sex

Paula Olsen and her ex-husband Walter give their reaction to the verdict