Italian authorities suspect arson caused the deaths Wednesday of three Gypsy sisters in Rome whose camper burst into flames as they slept.
The three sisters, aged 4, 8 and 20, were killed, but their parents and eight other siblings escaped the blaze in the Centocelle neighborhood.
The Italian news agency ANSA said prosecutors had opened an arson investigation after family members reported that they received threats in recent days and that a nearby camper was torched last week.
Italian politicians, including President Sergio Mattarella, denounced the crime, and Pope Francis sent his chaplain to comfort the bereaved family and offer "concrete assistance," the Vatican said.
It was not immediately clear whether the fire was the result of a vendetta inside the city's Gypsy community or an anti-Roma act by local residents. Rome police said they weren't excluding any lines of inquiry.
The neighborhood where Wednesday's fire occurred is near Roma squatter camps. The camper was parked in the otherwise empty parking lot of a shopping center.