$1500 is nothing. Turning that in is likely to not only get you local news media attention, but also probably some sort of viral facebook notoriety that ends up with someone starting a kickstarter or something to reward you for being a decent human being.
If he'd found a briefcase containing 5 million dollars and turned it in, then that would make him truly trustworthy. He'd probably be assassinated by a drug cartel shortly after though.