The Michigan Supreme Court has denied Sean Phillips request to appeal his conviction and sentencing for the unlawful imprisonment of his daughter.
The court issued the one-sentence ruling on Tuesday saying the application to appeal was denied "because we are not persuaded that the questions presented should be reviewed by this court."
The Michigan Court of Appeals also denied his appeal in Dec. 2013.
Phillips is currently serving 10-15 years in prison on the unlawful imprisonment charge in connection to the disappearance of his daughter, Katherine "Baby Kate" Phillips.
While serving his sentence, Phillips was charged with murder in his daughter's disappearance. Her body has never been found.
Baby Kate disappeared on June 29, 2011 while in the care of her father, Sean.
A letter, apparently written by Sean Phillips in prison, details what happened the day Baby Kate disappeared. Mason County Prosecutor Paul Spaniola said that the letter was given to investigative officers by a family member of Baby Kate.
In the letter, Phillips said he had put his daughter in a peaceful place.
The letter will be used as evidence in the murder trial.
Phillips is scheduled to be back in court on July 31 for a continuation of his preliminary hearing.