The amount is large enough to represent a meaningful financial alternative to whatever value the possessor currently expects to realize from the art. For someone who inherited the paintings from a criminal family member and has no mechanism for selling them, $10 million for returning them is a genuine alternative to continuing to hold unrecoverable assets.
The immunity language reflects the expired statute of limitations on the original theft. The museum and the FBI have indicated that someone who comes forward with the works may not face prosecution for the theft itself. This is meaningful: the primary criminal exposure for whoever now holds the paintings is not the thirty-six-year-old heist but the current possession of stolen property. The legal analysis would depend on individual circumstances, but the signal is clear—the goal is recovery, not prosecution.
The separate $100,000 reward for the finial signals the museum’s recognition that the collection may have been divided. If the finial is in different hands from the paintings—possibly in a location entirely unconnected to the Dorchester network—a separate reward gives whoever has the finial a reason to come forward even if they have no information about the larger collection.
The reward has been in place for three decades. Its existence is public and well known. Anyone in the criminal world who has had contact with the stolen works knows about it. The fact that no one has come forward for $10 million suggests either that the possessor values the works more than the reward, that they fear legal exposure despite the immunity signals, that they don’t believe they would actually receive the money, or that they are no longer capable of coming forward—dead, incarcerated, or otherwise unavailable.