HELSINKI  -  Flags in Finland flew at half-mast on Wednesday as the country mourned the killing of a 12-year-old by a classmate who opened fire and seriously injured two others. All public buildings and insti­tutions lowered their flags at 8:00 am (0500 GMT) on Wednesday, and the interior ministry encour­aged the whole country to participate in the day of grieving. On Tuesday morning, a 12-year-old Finnish boy opened fire at his school in Vantaa.