The amount might not be the issue. Rather, the right population might not be aware of the reward If so, this lack of reward knowledge could be a key difference.
For example, the family of a murder victim in the South had posted reward information on bill boards along interstates and in the city. The police tried to focus on an angry ex husband with an airtight alibi. The case then went cold for years.
Desperate, the family hired private detectives. The investigators suspected a killer hired by the ex. They also thought that the killer may have been hired from a nearby lower income, predominately black American rural area where the ex, though white, had connections going back decades.
One of the investigators was black, knew the local culture, and knew that even if the locals saw the billboards, the reward was out of sight and out of mind. He then told the family to give him the reward amount in cash.
Next, he went door to door and talked about church, local football- and the murder on porches and over kitchen tables. When leaving, he would take the cash out of the bag, show it- look, don't touch!- and promise that it would be paid and that one tipster could get it all.
With in days, the phone rang off the hook with meaningful tips. The police quickly arrested a laborer known to work for the ex on occasion. He then quickly rolled over on the ex.
In short, perhaps the reward needs to be directly shown to the right population in the right circumstances. Maybe, hit the Star Wars conventions with an attractive display?
