Authorities say they are not ruling anything out as they continue to search for Mollie Tibbetts, the 20-year-old University of Iowa student who disappeared from Brooklyn, Iowa on July 18.During a news conference Tuesday at the Poweshiek County Sheriff’s Office in Montezuma, Kevin Winker, of the Iowa Department of Public Safety's Investigative Operations Division, said investigators continue to follow up on all new leads they receive, but declined to give specifics.“Investigators are looking at all possible sources of information provided by people and obtained from technology,” he said.