A St. Paul-based home health care company is being investigated by the Minnesota Attorney General’s Office for fraudulently overbilling the state’s Medicaid program, which is designed to support low-income residents and people with disabilities. State investigators took computers, financial reports, rental agreements, and other documents from Bridges MN on Thursday, according to court documents filed last week. Authorities say they have already tracked $4 million in fraudulent billing over five years, with the possibility of more instances of fraud expected, according to a search warrant.