The Jackson County Sheriff’s Department is warning residents of a phone scam where callers claim to have kidnapped children. Law enforcement said the calls demand parents purchase gift cards at the Cookeville-area Walmart locations. Officials said the callers use personal information gathered from the internet to make the fraudulent kidnapping claims appear credible. The scammers demand that parents purchase gift cards once they are inside the retailer. Then, callers demand the gift card numbers be provided over the phone.