A Delaware man has pleaded guilty but mentally ill in the fatal stabbing of a psychiatrist who once treated him.

Twenty-two-year-old Christopher Frick entered the plea at a court hearing Friday. He faces a mandatory sentence of life in prison without parole at his Nov. 18 sentencing.

Frick was charged with killing 55-year-old Caroline Ekong, who was found dead in her home in October 2015.

Authorities say Frick later called 911 and said he had killed Ekong.

Three mental health experts concluded that Frick suffers from a host of mental disorders, but the judge found him competent to enter the plea.

Frick's attorney said he understands that what he did was wrong and that he needs to be punished, and that he has dedicated his life to Christianity.