Haters congratulated those behind a murder and an acid attack.

Police in Italy have tracked down two so-called 'haters' who posted vile, hate-filled messages on social media, in two high-profile but separate cases.

The first case related to the killing of Willy Monteiro Duarte, a Cape Verdian-Italian who was beaten to death by a gang in a town south of Rome earlier this month.

A hater, hiding behind the fake profile of 'Manlio Germano', published a post in which he celebrated the murder of Duarte, congratulating his killers, with the comment: "How happy I am that you got rid of that chimpanzee."

• Italy mourns Willy, beaten to death by gang

Police tracked down the man behind the comment, a young Neapolitan student living in Treviso, who is an IT specialist using fictitious accounts connected to service providers in Bulgaria and Korea.

The student now faces charges including incitement to commit crimes aggravated by racial hatred, which carries a penalty of up to eight years in prison, according to Italian media.

The second case involves Lucia Annibali, an Italian lawyer and politician with the liberal Italia Viva party, who is an acid attack survivor, as reported by Italian newspaper La Repubblica.

In 2013 her face was left permanently scarred after two men sent by her former boyfriend, Luca Varani, doused her in acid. Varani was sentenced to 20 years in jail for attempted murder and stalking, while the two men who threw the acid were sentenced to 12 years in prison.

In recent days police tracked down the hater behind the comment: "Luca Varani you are my hero. Honour and thanks to Luca Varani, you did your duty as a man," wrote the man, before referring to Annibali as "una misera infame" (which translates roughly as a "miserable disgrace.")

The individual, aged 53 and living in Rome, admitted responsibility for the comment, made using a fake name, and his case has been referred to judicial authorities, reports La Repubblica.

Photo of Lucia Annibali - La Repubblica