ess, even if the court holds that the initial encounter constituted a seizure, the prosecutor will argue that the seizure was lawful because Ann had reasonable suspicion based on specific, objective facts. Those facts include the time of day (night), the location (a museum housing valuable art), and Al's clothing (black).
This motion has little likelihood of succeeding. No seizure occurred until Ann tackled Al (merely asking Al a question on the street does not qualify). The officer witnessed Al toss the signaling device into the bushes, and retrieving that item from public property did not require a search warrant.
First, and foremost, this motion only concerns the use of Al's statements against Al. No other defendant has standing to challenge the admissibility of those statements against them.
Al's first statement to Ann ("I'm just the lookout!") is admissible against Al unless the first encounter was a seizure (see discussion of Motion #1). The best argument against admitting Al's second statement to Ann ("I'm just the lookout. They were going to take some of those Russian paintings.") is that Ann violated Al's Fifth Amendment right against self-incrimination by failing to give him Miranda warnings. According to the Supreme Court's decision in Miranda v. Arizona (1965), a police officer must inform any suspect in custody of his rights before interrogating him.
Custody is a broad term that includes deprivation of freedom in any significant way by the authorities. Here, Ann tackled Al, preventing him from leaving the area. He was not free to go, so he was in custody. The next part of the analysis is to determine whether Ann interrogated Al. "Any words or actions by police that the police should know are reasonably likely to elicit an incriminating response from the suspect" constitute an interrogation according to Rhode Island v. Innis (1980). Ann's query ("What's going on here, buddy?") satisfies that stand...