A group of Senate Republicans pressed Attorney General Eric H. Holder on Friday to explain the administration’s policy for U.S. fugitives in Cuba, including a convicted cop killer, following President Obama’s announced normalization of relations with the communist island nation. “As the nation’s chief law enforcement officer, do you support the normalization of relations with Cuba without the return of fugitives from justice for prosecution who have the blood of Americans, including law enforcement officers on their hands?” said the three senators in a letter to Mr. Holder. The letter was signed by Sens. Marco Rubio of Florida, Ted Cruz...