On 22 June 2005, Sommer and nine other former SS members were convicted by an Italian military court in La Spezia for the "continued murder with special cruelty" of 560 villagers at Sant'Anna di Stazzema. All ten were sentenced to life imprisonment and ordered to pay compensation payments. Sommer and four of his comrades appealed, but the sentences were confirmed in 2006 by a military court in Rome.