A Kenyan man living in the United States has been convicted in what prosecutors are calling one of the biggest Medicaid fraud scandals ever uncovered in the Northwestern US state of Washington.

According to a press release from the Washington State Attorney General’s office, a jury delivered a verdict of guilty on all 11 counts in a trial against Kenyan David Mungai Njenga. He is accused of running a fraudulent scheme to use stolen identities of real nurses to send unqualified imposter nurses into long-term healthcare facilities.