A 27-year-old finance police office has been arrested after shooting dead his ex-girlfriend's mother and sister with his service weapon in Cisterna di Latina, south of Rome, on Tuesday.
The double murder occurred following an argument between the policeman and the 22-year-old women who had recently broken up.
The mother and sister, 49 and 19 years old respectively, were killed after trying to intervene when the situation got violent.
The ex-girlfriend managed to save herself by locking herself in a bathroom until the police arrived.
It was initially reported that the man had killed his wife and daughter.
Gender-based violence is a major issue in Italy following a long series of femicides, including the murder of 22-year-old student Giulia Cecchettin by her ex-boyfriend last year in a case that shocked the nation.
Latina is a city of around 100,000 people founded in 1932 by Mussolini in the reclaimed Pontine Marshes.
It is one of Lazio's five provincial capitals along with Rome, Rieti, Viterbo and Frosinine.
Cisterna di Latina, the site of a major WWII battle, is about 10km nearer Rome than Latina, which is 55km from the capital.
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