Italian police arrested a man on Thursday suspected of killing a Nigerian refugee in a racist attack that has shocked Italy, further fuelling political debate on the long-running immigration crisis. Emmanuel Chidi Namdi, 36, was attacked on Tuesday in the small, central Italian town of Fermo, after coming to the defence of his wife, Chinyery Emmanuel, who was verbally abused by two Italians, locals said.Chinyery Emmanuel told police that her husband was knocked unconscious by a man wielding a road-sign pole."The assailant continued to kick and punch him even when he was lying on the ground," said priest Vinicio Albanesi, who had offered the couple shelter in a nearby centre that is home to more than 100 migrants and asylum seekers.Namdi died in hospital on Wednesday.The pair came to Italy last year on a boat from Libya after escaping an attack on their church in Nigeria by the Islamist militant group Boko Haram. Their child and both their parents died in that assault, friends told Italian media.Police said they had arrested Amedeo Mancini, 38, on suspicion of murder motivated by racism. The suspect's lawyer told AGI news agency that the dynamics of the incident had not yet been established.Italian Prime Minister Matteo Renzi dispatched his interior minister to the town on Thursday to discuss the killing with local authorities. "The government today is in Fermo, alongside father Vinicio and the local institutions in memory of Emmanuel. Against hatred, racism and violence," Renzi said in a tweet.Politicians from all parties condemned the killing, but the leader of the right-wing Northern League party, Matteo Salvini, said the incident showed immigration had to be controlled."Whoever kills, rapes or assaults another human being has to be punished. Without exception. Regardless of race," he said in a post on Facebook, adding: "It is ever more clear that illegal immigration is out of control ... and will bring no good."Italy has been on the frontline of Europe's immigration crisis. About 170,000 migrants reached Italy by sea in 2014 and 153,800 came in 2015. So far this year, more than 75,000 migrants have arrived, the vast majority of them Africans.Many have moved swiftly on to wealthier countries in northern Europe, but tightening border controls mean increasing numbers are remaining in Italy and are being sent to reception centres around the country.The Roman Catholic Church has looked to provide homes to migrants and father Albanesi told reporters that the arrival of Africans had caused problems in Fermo. "More than hate, I see discomfort," he said."People see folk of different ethnicities begging, selling goods ... wandering around town. But the problem is also that the migrants have to wait one or even two years to hear if their asylum requests have been accepted." ..