BERLIN—A former imam at a radical mosque in Germany was convicted Wednesday of being a member of the ISIS terrorist group and sentenced to 10-1/2 years in prison. The state court in Celle in northern Germany convicted Ahmad Abdulaziz Abdullah A., who goes by the alias Abu Walaa, of membership in a foreign terrorist organization as well as terror financing and being an accessory to preparing a serious act of violence, a court statement said. The court found that Abu Walaa and his network radicalized young people in northern and western Germany and sent them to areas controlled by ISIS, the dpa news agency reported. Three co-defendants were given prison sentences ranging from four years and two weeks to eight years for supporting ISIS, among other offenses. The verdict against Abu Walaa, a 37-year-old Iraqi citizen, ended a trial that began in September 2017. Abu Walaa was the imam at …