The trial of three former German SS officers, charged with killing 560 civilians in a 1944 massacre in northern Italy, began at a military court in La Spezia on Tuesday. Survivors of one of Italy's worst wartime massacres and relatives of the victims have been called to give evidence, but the defendants are all being tried in absentia. All in their eighties, the suspects are also under investigation in Germany, where they live, and are unlikely to be extradited to Italy to participate in the trial. The court will be deciding whether to indict four more suspects on the same charges, and the trial may be suspended for several more weeks so that all seven suspects can be tried together. The massacre occurred days after British troops liberated Florence in 1944, when hundreds of SS troops surrounded the Tuscan village of Sant'Anna di Stazzema. According to witnesses, they rounded up the villagers and shot them. Others were forced into cellars and other enclosed spaces and systematically killed with hand grenades. Prosecutors believe the SS were seeking to stop partisans in the village, which had been flooded with refugees, but most of those killed were women, children and the elderly.