DC Superior Court Judge Robert Hildum ordered a mental competency exam for a stabbing defendant on July 28. Jacqueline Grace, 47, is charged with assault with a dangerous weapon for her alleged involvement in an altercation with a homeless woman on July 25 at the 900 block of G Street, NW in front of the Martin Luther King Jr. Memorial Library. According to court documents, Grace allegedly pointed a knife at the woman, lacerating her hand durin…