MINSK, Belarus (AP) — One of two men who allegedly carried out a subway bombing attack in Belarus that killed 15 people and wounded hundreds more has been executed, his mother said Saturday.Lubov Kovaleva said she had received official notification about the execution of her son, Vladislav Kovalev.Kovalev and Dmitry Konovalov, both 26 years old, were convicted in November of planting a bomb at the busiest subway station in Belarus' capital, Minsk, last April.