The brutal murder of an elderly couple in Sicily has become a political issue in Italy following the arrest of an African asylum seeker who was allegedly implicated in the killings.

The accused killer, 18-year-old Mamadou Kamara from the Ivory Coast, has been a resident of the Mineo refugee centre in Sicily – the largest such facility in Europe – since 8 June. According to Italian media reports, Kamara was arrested on Sunday after he was found entering Mineo with a bag containing a phone that allegedly belonged to the victims. His pants were allegedly stained with blood.

One victim, Victor Solano, 68, was found in his nearby home with his throat slit and his Spanish wife, Mercedes Ibanez, 70, was found in the courtyard of the couple’s apartment building, having apparently fallen from the balcony.

The daughter of the victims, Rosita Solano, blamed the Italian government for the murders, saying it allowed “immigrants to come here and do what they want, even rob and kill us”. She singled out the Italian prime minister, Matteo Renzi, and interior minister, Angelino Alfano, who have resisted political pressure from some critics to stop saving tens of thousands of migrants who have attempted the treacherous crossing from northern Africa to Italy’s southern shore.

“Renzi, come here and explain it to me,” she said in a video interview with La Repubblica.

Anti-immigrant politicians, led by Matteo Salvini, the head of the rightwing Northern League, seized on the remarks. “From what war was this guy escaping??? If he’s guilty, jail for life, with HARD LABOUR!,” Salvini said on Twitter and his Facebook page. He called for the immediate closure of the migrant centre in Mineo.

Coppia di anziani massacrata a Catania, fermato un "profugo". Da che guerra scappava questo tizio??? #Salvini pic.twitter.com/dHIHtnIWUN — Matteo Salvini (@matteosalvinimi) August 31, 2015

Another rightwing politician from the Fratelli d’Italia party called on Renzi to explain himself to the victims’ daughter, saying the Mineo migrant reception centre was not properly monitored.

The mayor of Palagonia, where the murders took place, took a more measured tone, saying more police patrols were needed “migrants or not”, because the area required more security.

More than 100,000 migrants and refugees have arrived in Italy this year, tens of thousands of whom have been rescued by Italian and other European rescue crews.

Migrants generally have not faced a hostile reception in Italy, but there have been some incidents over the past few months of violence and antagonism against the new arrivals provoked by unsubstantiated claims the migrants are violent and dangerous. The murders in Sicily are likely to fuel anger and concern among some Italians who say the wave of new migrants poses a domestic security risk.

The political tensions in Italy come as EU interior and justice ministers said they would meet in two weeks in Brussels to find “concrete steps” to cope with the escalating migration issue.

Renzi said on Sunday that he believed the EU would adopt a set of uniform rules for refugees, replacing a patchwork of laws.