Health officials are investigating a series of potentially related Salmonella illnesses in multiple states, one of them known to be Massachusetts. The Massachusetts Department of Public Health revealed Thursday that it is investigating a possible cluster of Salmonella illnesses in the state, according to Fox25. The department said the potential multistate outbreak is also being investigated by federal health officials from the U.S. Food and Drug Administration and the U.S. Centers for Disease Control and Prevention. The source of the illnesses remains unknown, according to the MA Department of Public Health.