The Minnesota Supreme Court rejected the appeal Wednesday of a Mahnomen County sheriff deputy's convicted killer.

Thomas Lee Fairbanks, 38, handled the appeal petition to the court without an attorney. His focus was the lapse between Deputy Christopher Dewey's injuries when he was shot in the head and abdomen by Fairbanks in 2009 and his death in hospice care in August 2010.

Fairbanks was convicted by a jury in 2011 of first-degree murder and four counts of first-degree assault following Dewey's death. He was sentenced to life in prison without parole. First-degree murder convictions are automatically appealed to the Minnesota Supreme Court.

In his appeal, Fairbanks argued that a lung condition and Dewey's family decision to refuse further medical treatment caused his death. The court rejected the argument.

Fairbanks also raised a claim that he didn't receive a fair trial for a variety of reasons. The court ruled that none of the claims were supported by facts or a substantive argument.