Sen. Ron Johnson, R-Wis., charged Thursday that Medicaid expansion under Obamacare is fueling the opioid crisis in America, and said he has evidence to support his theory.

Johnson sent a letter Thursday to the Health and Human Services inspector general that said he used open-source databases and “shockingly identified 261 people who had been convicted – in states ranging from Pennsylvania to Vermont – of exploiting Medicaid cards to obtain opioids, which were often resold at enormous profit.”