William J. Fell, the parking meter repairman in Alexandria VA, skimmed $170,000 worth of coins from parking meters over the course of one year.

The 61-year-old city employee did it, police say, by going to work at 3 a.m., well before his shift started. He would jump in his city truck and, under the cover of darkness, empty into bags the contents of coin canisters from parking meters all over Old Town, according to court documents.

Done carefully, taking a constant percentage, this would be hard to detect based purely on tracking total revenue.  However, at some point the city raised the parking rate to $1 per hour.  How do you adjust your skimming rate to avoid detection?

Last year, the city took in just over $1 million in revenue from its 1,040 parking meters, officials said. But they realized something was amiss. They had raised the rates to $1 an hour but weren’t getting as much money as they expected.

Oops.  If Mr. Fell thinks that the city knows the correct elasticity of demand, then he should keep the same skim rate as before.  That way the city sees exactly the percentage change in revenue they were expecting.  Apparently Mr. Fell thought that the city had overestimated demand elasticity and therefore was expecting a smaller increase in revenue than they were actually getting so he raised his skim rate to compensate.

Of course, alternative explanation is that Mr. Fell is not motivated by standard economic incentives:

That much money in quarters, dimes and nickels would weigh at least four tons. If it was all in nickels, it would weigh nearly 19 tons.

Police were perplexed after they subpoenaed Fell’s bank accounts but did not see any of the money there. That was when they decided that it might be in his home and executed a search warrant April 15 — tax day.

Police say Fell, who lives alone, did not appear to use the money for anything specific and mostly just kept it in his home.