(CNN)Dozens of African immigrants protested in central Florence on Monday evening after an Italian man shot dead a Senegalese trader.
The suspect, 65-year-old Roberto Pirrone, told Italian police he wanted to kill himself for "economic reasons," according to a report from Italy's ANSA news agency.
He even penned a suicide note to his family, which was uncovered in his home in Oltrarno, a Florence neighborhood.
But instead of taking his own life, Pirrone opened fire and killed 54-year-old trader Idy Dienec on Vespucci bridge in central Florence earlier Monday, police told ANSA.
A spokesman for Italian police confirmed the details in the ANSA report and told CNN the suspect was in custody, adding that the murder was not racially motivated.
But the Senegalese community pointed out that the killing came a day after a parliamentary election in Italy in which immigration has been one of the main issues. Anti-immigrant and populist parties made big gains in Sunday's vote.
"They have to explain why he shot," Pape Diaw, spokesman for the community, told ANSA before the march. "They needn't tell us he's just a madman. We're angry and we don't like that this happened during this political moment in Italy."
"Italy has become a country where blacks are shot on the street," Diaw told Reuters.
Florence Mayor Dario Nardella tweeted a statement saying that the killing of Dienec "at the hands of a deranged" man had struck the heart of Florence. He also appealed to people for calm.
"We understand the pain of the Senegalese community but the violent protest of this evening in the center is unacceptable," he said. "Violent people from all sides must be entrusted to police."
Videos from the rally show a few people overturning garbage bins, motor scooters, and breaking flower pots in the center of Florence.
In 2011, an Italian man affiliated with the far-right, Gianluca Casseri, opened fire with a large handgun and killed two Senegalese traders in Florence.