The children of Melissa Hortman and her husband Mark Hortman are speaking out on their parents' murders. “They were the bright lights at the center of our lives, and we can’t believe they are gone," Sophie and Colin Hortman wrote in a statement obtained by PEOPLE Monday.

"The best way to honor our parents' memory is to do something, whether big or small, to make our community just a little better for someone else.”

Sophie and Colin Hortman are responding to the fatal shooting of their parents, Minnesota state Rep. Melissa Hortman and Mark Hortman.