The Supreme Court has turned away an appeal from a federal death row prisoner who wants the courts to consider evidence that one federal judge said "is virtually guaranteed" to show the inmate is mentally retarded and thus barred from being executed.

The court did not comment Monday in rejecting an appeal from Bruce Carneil Webster. He was sentenced to death more than 14 years ago and has since tried in vain to persuade federal judges that he is mentally retarded.

Evidence recently provided by the Social Security Administration shows three federal doctors determined Webster was mentally retarded when he applied for disability benefits in 1993, a year before 16-year-old Lisa Rene was kidnapped and killed.

Rene was raped, beaten and buried alive after her abduction was recorded in a desperate 911 call.