In her latest mystery, author Lori Armstrong's character Mercy Gunderson is back in "Merciless." A former Army sniper, Gunderson investigates a highly-trained military assassin who may have his sights set on Mercy as his next victim. Anderson will sign copies of her new book Saturday at 2 p.m. at Books-A-Million in Rapid City and Tuesday, January 22, at 5 p.m. at the Sturgis Public Library. Armstrong currently serves on the Board of Directors for the Mystery Writers of America.