Gov. Tim Walz called Thursday for Minnesota to increase criminal penalties for Medicaid fraud in response to the FBI’s investigation into autism service providers.

The FBI searched at least two Minnesota autism centers Thursday as it investigated “substantial evidence” of fraudulent Medicaid claims made by many companies participating in the state program. The state-funded Early Intensive Developmental and Behavioral Intervention (EIDBI) program, which serves people under 21 with autism spectrum disorder, has experienced exponential growth in Medicaid billing. Reimbursement claims soared from $1.7 million in 2017, the first year of the program, to nearly $400 million last year and again this year.

Federal law enforcement suspects many autism centers are billing for services not actually provided.

“This pisses me off unlike anything else,” Walz told the Star Tribune in an interview Thursday afternoon. “They’re stealing from us … You’ve got to increase the penalty on these crimes. These are crimes against children, in my opinion.”