"All the guns used in Saturday's massacre at a Pittsburgh synagogue had been purchased legally, a federal official said Wednesday. Authorities allege Robert Bowers opened fire at the Tree of Life synagogue as three congregations gathered to celebrate Shabbat services Saturday morning, killing 11 people and injuring six others in what's believed to the deadliest anti-Semitic attack in US history. Bowers used a Colt AR-15 rifle and three Glock .357 handguns during the attack, police have said."