The state may have erroneously paid up to $2.5 million on health care through the Medicaid program for more than 300 low-income residents after they died, according to a state legislative audit released Wednesday. The payments were discovered after auditors checked the names of Medicaid recipients from January 2008 through August of this year against Social Security records to capture those who died out of state. The program had relied on state vital statistics to track deaths. Auditors couldn't say how many payments were fraudulent or even illegitimate ? some medical bills could have been sent after a patient's death. But state health officials pledged to investigate.