One of Iowa’s natural gas companies is being investigated by the Iowa Utilities Board. Consumer Advocate Gary Stewart says state officials received some anonymous tips about People’s Natural Gas. Stewart says the anonymous letters accuse People’s employees of giving higher-priced natural gas to its retail customers and finding lower-priced natural gas for the other companies. Stewart says the allegations are being investigated by regulators in Iowa, Minnesota, Missouri and Michigan. Iowa Utilities Board members launched the investigation this month. People’s and its parent company have pledged full cooperation with the investigation, but say the anonymous letters “mischaracterize” their operation. People’s is not the dominant natural gas supplier in Iowa. MidAmerican and Alliant serve a majority of Iowa natural gas customers.