An inmate convicted in one of New York's most notorious police killings - and more recently accused of getting a prison guard pregnant - was declared mentally fit on Thursday for a death penalty proceeding.

In a written ruling, U.S. District Court Judge Nicholas Garaufis rejected arguments by Ronell Wilson's lawyers that he should be automatically spared a death sentence on grounds he is mentally disabled.

"The court holds that Wilson is not mentally retarded and was not mentally retarded at the time of the crime," the judge said. "This does not mean he will receive - or deserves to receive - the death penalty, but only that any such penalty would not violate the Federal Death Penalty Act or the Eighth Amendment."

The judge cited testing over the years that nearly always found that Wilson had an IQ higher than 70 - considered a benchmark for mental disability.

The decision in federal court in Brooklyn made no mention of the charges brought Tuesday against the prison guard, accusing her of having an illegal affair with an inmate. The woman is eight months pregnant with a child that's believed to be Wilson's.

Wilson, 30, was a young gang member on Staten Island when he was convicted in the point-blank shootings of undercover officers James Nemorin and Rodney Andrews in a 2006 illegal gun sting gone awry. The officers were both shot in the back of the head.

At trial, a jury found Wilson guilty in the killings and sentenced him to death. But the sentence was thrown out in 2010 by an appeals court based on prosecutorial error.