A Seattle physician has admitted that he filed hundreds of fraudulent Medicare claims for nursing home services, including some claims for residents who were deceased, according to news reports.

John C. Chen, M.D., pleaded not guilty to the charges in federal court in September. However, he changed his plea Wednesday, The Associated Press reported.

Chen was charged with submitting nearly 900 fraudulent claims, including claims for services supposedly rendered to deceased beneficiaries, and some dated during times when he was out of the country, according to the AP.

His charges carry a maximum sentence of 45 years in prison, the AP reported. A sentencing hearing has not yet been scheduled.

The Medicare contractor that handled the claims is based in North Dakota, so the case is being tried there rather than Washington.