As law enforcement officials scrambled to find a motive behind theArkansas grocery store shooting that killed three and wounded 11, harrowing tales of people clambering for cover began to surface, including how a mom and her children cowered in a freezer. Gunfire erupted at the Mad Butcher store in Fordyce, Ark., about an hour south of Little Rock, at about 11:30 a.m. Friday, sending people inside the grocery in a frantic search for safety. Katrina Doherty, 39, was shopping with her 18-year-old daughter and 4-year-old son when the shooting began, leaving the mother initially thinking something…