Final answer:
The second officer must respect the defendant's request for an attorney and cannot question them about an unrelated crime unless the defendant's attorney is present since the right to counsel has been invoked.
Step-by-step explanation:
When a defendant, who is under arrest for robbery, invokes their right to an attorney in response to the Miranda warning, law enforcement must respect this request. If three hours later, a different law enforcement officer (LEO) wishes to question the suspect about a separate crime, in this case, arson, they still need to adhere to the invoked right to counsel. The suspect has already asserted their right to have an attorney present during questioning, as guaranteed by the Escobedo v. Illinois and Miranda v. Arizona cases which affirmed the due process rights of individuals in police custody.
Therefore, the second officer cannot legally proceed with questioning about the arson without the defendant's attorney present. This is maintained even if the crimes in question are unrelated. The landmark decision in Miranda v. Arizona enshrined the necessity to advise criminal suspects of their rights to remain silent and to have an attorney, establishing safeguards to protect against self-incrimination and ensuring voluntary statements within custodial interrogations. Additionally, as per the Montejo v. Louisiana ruling, even if a defendant has asserted their right to counsel, they may waive this right at a later time. However, this waiver should be made clearly and voluntarily outside the context of a police-initiated interrogation.